RTCPeerConnection: idpvalidationerror event - Web APIs
an idpvalidationerror event informs the target, a rtcpeerconnection object, that the identity provider (idp) encountered an error when trying to validate an identity assertion. an event handler for this event can be added via the rtcpeerconnection.onidpvalidationerror property. bubbles no cancelable no interface rtcidentityerrorevent event handler property onidpvalidationerror important: this event is no longer used; it was removed from the specification long ago. instead, you should watch for the rtcpeerconnection.peeridentity promise to be rejected with an operationerror. ...
...dler property onidpvalidationerror important: this event is no longer used; it was removed from the specification long ago. instead, you should watch for the rtcpeerconnection.peeridentity promise to be rejected with an operationerror. specifications specification status comment webrtc 1.0: real-time communication between browsersthe definition of 'idpvalidationerror' in that specification. candidate recommendation initial definition. ...

ServiceWorkerContainer.onerror - Web APIs
the onerror property of the serviceworkercontainer interface is an event handler fired whenever an error event occurs in the associated service workers. syntax serviceworkercontainer.onerror = function(errorevent) { ... ...
... the onerror property of the serviceworkercontainer interface is an event handler fired whenever an error event occurs in the associated service workers. syntax serviceworkercontainer.onerror = function(errorevent) { ... ...

SpeechRecognitionError.error - Web APIs
syntax var myerror = event.error; value a domstring naming the type of error. the possible error types are: no-speech no speech was detected. aborted speech input was aborted in some manner, perhaps by some user-agent-specific behavior like a button the user can press to cancel speech input. audio-capture audio capture failed. network network communication required for completing the recognition failed. ...
...acy or user preference. in this case it would allow another more suitable speech recognition service to be used instead. ...

SpeechRecognitionError.message - Web APIs
the message read-only property of the speechrecognitionerror interface returns a message describing the error in more detail. this speechrecognitionerror interface was renamed to speechrecognitionerrorevent in the web speech api specification. syntax var myerrormsg = event.message; value a domstring containing more details about the error that was raised. note that the spec does not define the exact wording of these messages — this is up to the implementors to decide upon. ...
... interface was renamed to speechrecognitionerrorevent in the web speech api specification. syntax var myerrormsg = event.message; value a domstring containing more details about the error that was raised. note that the spec does not define the exact wording of these messages — this is up to the implementors to decide upon. ...

SpeechRecognitionError - Web APIs
the speechrecognitionerror interface of the web speech api represents error messages from the recognition service. this speechrecognitionerror interface was renamed to speechrecognitionerrorevent in the web speech api specification. properties speechrecognitionerror also inherits properties from its parent interface, event. speechrecognitionerror.error read only returns the type of error raised. speechrecognitionerror.message read only returns a message describing the error in more detail. ...
...recognitionerrorevent in the web speech api specification. properties speechrecognitionerror also inherits properties from its parent interface, event. speechrecognitionerror.error read only returns the type of error raised. speechrecognitionerror.message read only returns a message describing the error in more detail. ...

SpeechRecognitionErrorEvent.error - Web APIs
syntax var myerror = event.error; value a domstring naming the type of error. the possible error types are: no-speech no speech was detected. aborted speech input was aborted in some manner, perhaps by some user-agent-specific behavior like a button the user can press to cancel speech input. audio-capture audio capture failed. network network communication required for completing the recognition failed. not-allowed the user agent disallowed any speech input from occurring for reasons of security, privacy or user preference. ...
...acy or user preference. in this case it would allow another more suitable speech recognition service to be used instead. bad-grammar there was an error in the speech recognition grammar or semantic tags, or the chosen grammar format or semantic tag format was unsupported. language-not-supported the language was not supported. examples var recognition = new speechrecognition(); recognition.onerror = function(event) { console.log('speech recognition error detected: ' + event.error); console.log('additional information: ' + event.message); } specifications specification status comment web speech apithe definition of 'error' in that specification. draft ...

XMLHttpRequestEventTarget.onerror - Web APIs
the xmlhttprequesteventtarget.onerror is the function called when an xmlhttprequest transaction fails due to an error. syntax xmlhttprequest.onerror = callback; values callback is the function to be executed when the request fails. ...
... the xmlhttprequesteventtarget.onerror is the function called when an xmlhttprequest transaction fails due to an error. syntax xmlhttprequest.onerror = callback; values callback is the function to be executed when the request fails. ...

onerror - Archive of obsolete content
« xul reference home onerror type: script code this event is sent to an image element when an error occurs loading the image. ...

onerrorcommand - Archive of obsolete content
« xul reference home onerrorcommand type: script code this event handler is called when an error occurs when selecting a result from the popup. ...

nsIDOMGeoPositionError
last changed in gecko 1.9.2 (firefox 3.6 / thunderbird 3.1 / fennec 1.0) inherits from: nsisupports attributes attribute type description code short numerical error code; see error constants for a complete list. read only. message domstring human readable error message. read only. gecko 1.9.2 note the message attribute was removed in gecko 1.9.2 (firefox 3.6). ...

nsIDOMGeoPositionErrorCallback
the nsidomgeopositionerrorcallback interface is used to represent an object that receives callback notifications when geolocation errors occur. dom/interfaces/geolocation/nsidomgeopositionerrorcallback.idlscriptable please add a summary to this article. last changed in gecko 1.9.1 (firefox 3.5 / thunderbird 3.0 / seamonkey 2.0) method overview void handleevent(in nsidomgeopositionerror position); methods handleevent() called to handle a geolocation error. void handleevent( in nsidomgeoposition position ); parameters position the error that occurred, as an nsidomgeopositionerror object. ...

AbstractWorker.onerror - Web APIs
the abstractworker.onerror property of the abstractworker interface represents an eventhandler, that is a function to be called when the error event occurs and bubbles through the worker. syntax myworker.onerror = function() { ... }; example the following code snippet shows creation of a worker object using the worker() constructor and setting up of an onerror handler on the resulting object: var myworker = new worker('worker.js'); myworker.onerror = function() { console.log('there is an error with your worker!'); } specifications specification status comment html living standardthe definition of 'abstractworker.onerror' in that specification. living standard ...

EventSource.onerror - Web APIs
the onerror property of the eventsource interface is an eventhandler called when an error occurs and the error event is dispatched on an eventsource object. syntax eventsource.onerror = function examples evtsource.onerror = function() { console.log("eventsource failed."); }; note: you can find a full example on github — see simple sse demo using php. specifications specification status comment html living standardthe definition of 'onerror' in that specification. living standard initial definition ...

onerror - Web APIs
the filereader onerror handler receives an event object, not an error object, as a parameter, but an error can be accessed from the filereader object, as instanceoffilereader.error // callback from a <input type="file" onchange="onchange(event)"> function onchange(event) { var file = event.target.files[0]; var reader = new filereader(); reader.onerror = function(event) { alert("failed to read file!\n\n" + reader.error); reader.abort(); // (...does this do anything useful in an onerror handler?) }; reader.readastext(file); } ...

GeolocationPositionError.message - Web APIs
the geolocationpositionerror.message read-only property returns a human-readable domstring describing the details of the error. syntax let msg = geolocationpositionerrorinstance.message value a human-readable domstring describing the details of the error. specifications specification status comment geolocation apithe definition of 'geolocationpositionerror.message' in that specification. recommendation initial definition ...

HTMLMediaElement.onerror - Web APIs
the onerror property of the htmlmediaelement interface is the eventhandler for processing error events. the error event fires when some form of error occurs while attempting to load or perform the media. syntax htmlmediaelement.onerror = eventlistener; value a function which serves as the event handler for the error event. when an error occurs, the specified function will be called. if null, no error handler is in effect. specifications specification status comment html living standardthe definition of 'onerror' in that specification. living standard ...

FileHandle.onerror - Web APIs
this feature is non-standard and is not on a standards track. do not use it on production sites facing the web: it will not work for every user. there may also be large incompatibilities between implementations and the behavior may change in the future. summary specifies an event listener to receive error events. these events occur when something goes wrong. syntax instanceoffilehandle.onerror = funcref; where funcref is a function to be called when the error event occurs. specifications specification status comment filesystem api editor's draft draft proposal. ...

LockedFile.onerror - Web APIs
this feature is non-standard and is not on a standards track. do not use it on production sites facing the web: it will not work for every user. there may also be large incompatibilities between implementations and the behavior may change in the future. summary specifies an event listener to receive error events. these events occur when something goes wrong. syntax instanceoflockedfile.onerror = funcref; where funcref is a function to be called when the error event occurs. specifications specification status comment filesystem api editor's draft draft proposal. ...

NDEFReader.onerror - Web APIs
the onerror property of ndefreader interface of the web nfc api is called whenever an error occurs during reading of nfc tags, e.g. when tags leave the reader's magnetic induction field. specifications specification status comment web nfc, ndefreader.onerror draft initial definition. ...

Notification.onerror - Web APIs
note: this feature is available in web workers. the onerror property of the notification interface specifies an event listener to receive error events. these events occur when something goes wrong with a notification (in many cases an error preventing the notification from being displayed.) syntax notification.onerror = function() { ... }; specifications specification status comment notifications apithe definition of 'onerror' in that specification. living standard initial specification. ...

RTCPeerConnection: idpassertionerror event - Web APIs
an idpassertionerror event informs the target, a rtcpeerconnection object, that the identity provider (idp) encountered an error when trying to generate an identity assertion. an event handler for this event can be added using the rtcpeerconnection.onidpassertionerror property. bubbles no cancelable no interface rtcidentityerrorevent event handler property onidpassertionerror warning: this event is no longer used; instead, you can detect an assertion error by detecting when the promise returned by rtcpeerconnection.peeridentity is rejected. specifications specification status comment webrtc 1.0: real-time communication between browsersthe definition of 'idpassertionerror' in that specification. candidate rec...

SpeechRecognition.onerror - Web APIs
the onerror property of the speechrecognition interface represents an event handler that will run when a speech recognition error occurs (when the error event fires.) syntax myspeechrecognition.onerror = function() { ... }; examples var recognition = new speechrecognition(); recognition.onerror = function(event) { console.log('speech recognition error detected: ' + event.error); } specifications specification status comment web speech apithe definition of 'onerror' in that specification. draft ...

SpeechRecognitionErrorEvent.message - Web APIs
the message read-only property of the speechrecognitionerrorevent interface returns a message describing the error in more detail. syntax var myerrormsg = event.message; value a domstring containing more details about the error that was raised. note that the spec does not define the exact wording of these messages — this is up to the implementors to decide upon. examples var recognition = new speechrecognition(); recognition.onerror = function(event) { console.log('speech recognition error detected: ' + event.error); console.log('additional information: ' + event.message); } specifications specification status comment web speech apithe definition of 'message' in that specification. draft ...

SpeechRecognitionErrorEvent - Web APIs
the speechrecognitionerrorevent interface of the web speech api represents error messages from the recognition service. properties speechrecognitionerrorevent also inherits properties from its parent interface, event. speechrecognitionerrorevent.error read only returns the type of error raised. speechrecognitionerrorevent.message read only returns a message describing the error in more detail. examples var recognition = new speechrecognition(); recognition.onerror = function(event) { console.log('speech recognition error detected: ' + event.error); console.log('additional information: ' + event.message); } specifications specification status comment web speech apithe definition of 'speechrecognitionerrorevent' in that specification. draft ...

WebSocket.onerror - Web APIs
the websocket interface's onerror event handler property is a function which gets called when an error occurs on the websocket. you can also add an error event handler using addeventlistener(). syntax websocket.onerror = eventhandler; value a function or eventhandler which is executed whenever an error event occurs on the websocket connection. example websocket.onerror = function(event) { console.error("websocket error observed:", event); }; specifications specification status comment html living standardthe definition of 'websocket: onerror' in that specification. living standard initial definition ...

WorkerGlobalScope.onerror - Web APIs
the onerror property of the workerglobalscope interface represents an eventhandler to be called when the error event occurs and bubbles through the worker. syntax self.onerror = function() { ... }; example the following code snippet shows an onerror handler set inside a worker: self.onerror = function() { console.log('there is an error inside your worker!'); } specifications specification status comment html living standardthe definition of 'workerglobalscope.onerror' in that specification. living standard ...

XDomainRequest.onerror - Web APIs
an event handler which is called when an xdomainrequest encounters an error. note: there is no way to determine the cause of the error from the xdomainrequest interface. syntax xdr.onerror = funcref; parameters funcref a function to call when an error occurs. example var xdr = new xdomainrequest(); xdr.open("post", "http://example.com/api/method"); xdr.onerror = function(){ //handle error } xdr.onload = function(){ //handle response with xdr.responsetext } xdr.send("param1=value1&param2=value2"); specification not part of any specification. ...

Index - Web APIs
22 abstractworker api, abstract, abstractworker, interface, reference, sharedworker, web workers, web workers api, worker the abstractworker interface of the web workers api is an abstract interface that defines properties and methods that are common to all types of worker, including not only the basic worker, but also serviceworker and sharedworker. 23 abstractworker.onerror api, abstractworker, eventhandler, property, reference, web workers, workers, onerror the abstractworker.onerror property of the abstractworker interface represents an eventhandler, that is a function to be called when the error event occurs and bubbles through the worker. 24 accelerometer api, accelerometer, accelerometer api, generic sensor api, interface, reference, se...
...vents the eventsource() constructor returns a newly-created eventsource, which represents a remote resource. 1263 eventsource.close() api, eventsource, method, reference, server-sent events, close the close() method of the eventsource interface closes the connection, if one is made, and sets the eventsource.readystate attribute to 2 (closed). 1264 eventsource.onerror api, event handler, eventsource, property, reference, server-sent events, onerror the onerror property of the eventsource interface is an eventhandler called when an error occurs and the error event is dispatched on an eventsource object. 1265 eventsource.onmessage api, event handler, eventsource, property, reference, server-sent events, onmessage the onmessage prop...
...ds on which of the methods was used to initiate the read operation. 1349 filereader: abort event api, event, filereader, progressevent, reference, web, abort the abort event is fired when a read has been aborted: for instance because the program called filereader.abort(). 1350 filereader: error event api, error, event, filereader, progressevent, reference, web, onerror the error event is fired when the read failed due to an error (for example, because the file was not found or not readable). 1351 filereader: load event api, event, filereader, web, load the load event is fired when a file has been read successfully. 1352 filereader: loadend event api, event, filereader, progressiveevent, web, loadend the loadend ev...
...And 40 more matches

Using IndexedDB - Web APIs
osest lower integer and the transaction may not start, nor the upgradeneeded event trigger. so for example, don't use 2.4 as a version number: var request = indexeddb.open("mytestdatabase", 2.4); // don't do this, as the version will be rounded to 2 generating handlers the first thing you'll want to do with almost all of the requests you generate is to add success and error handlers: request.onerror = function(event) { // do something with request.errorcode! }; request.onsuccess = function(event) { // do something with request.result! }; which of the two functions, onsuccess() or onerror(), gets called? if everything succeeds, a success event (that is, a dom event whose type property is set to "success") is fired with request as its target. once it is fired, the onsuccess() function on ...
... if everything succeeds, a success event (that is, a dom event whose type property is set to "success") is fired with request as its target. once it is fired, the onsuccess() function on request is triggered with the success event as its argument. otherwise, if there was any problem, an error event (that is, a dom event whose type property is set to "error") is fired at request. this triggers the onerror() function with the error event as its argument. the indexeddb api is designed to minimize the need for error handling, so you're not likely to see many error events (at least, not once you're used to the api!). in the case of opening a database, however, there are some common conditions that generate error events. the most likely problem is that the user decided not to give your web app permiss...
...e user allowed your request to create a database, and you've received a success event to trigger the success callback; what's next? the request here was generated with a call to indexeddb.open(), so request.result is an instance of idbdatabase, and you definitely want to save that for later. your code might look something like this: var db; var request = indexeddb.open("mytestdatabase"); request.onerror = function(event) { console.log("why didn't you allow my web app to use indexeddb?!"); }; request.onsuccess = function(event) { db = event.target.result; }; handling errors as mentioned above, error events bubble. error events are targeted at the request that generated the error, then the event bubbles to the transaction, and then finally to the database object. if you want to avoid adding...
...And 14 more matches

indexed-db - Archive of obsolete content
experimental exposes the indexeddb api to add-ons. usage scripts running in web pages can access indexeddb via the window object. ...
...dow.indexeddb.open("mydatabase"); request.onerror = function(event) { console.log("failure"); }; request.onsuccess = function(event) { console.log("success"); }; because your main add-on code can't access the dom, you can't do this. so you can use the indexed-db module to access the same api: var { indexeddb } = require('sdk/indexed-db'); var request = indexeddb.open('mydatabase'); request.onerror = function(event) { console.log("failure"); }; request.onsuccess = function(event) { console.log("success"); }; most of the objects that implement the indexeddb api, such as idbtransaction, idbopendbrequest, and idbobjectstore, are accessible through the indexeddb object itself. the api exposed by indexed-db is almost identical to the dom indexeddb api, so we haven't repeated its documentat...
...r: the button labeled "add" adds the title of the current tab to a database, while the button labeled "list" lists all the titles in the database. the add-on implements helper functions open(), additem() and getitems() to open the database, add a new item to the database, and get all items in the database. ...
...And 4 more matches

RTCPeerConnection - Web APIs
tively gathering candidates—changes.onidentityresult the rtcpeerconnection.onidentityresult event handler is a property containing the code to execute when the identityresult event, of type rtcidentityevent, is received by this rtcpeerconnection. ...
...ntityresult the rtcpeerconnection.onidentityresult event handler is a property containing the code to execute when the identityresult event, of type rtcidentityevent, is received by this rtcpeerconnection. ...
...ing the code to execute when the identityresult event, of type rtcidentityevent, is received by this rtcpeerconnection. such an event is sent when an identity assertion is generated, via getidentityassertion() or during the creation of an offer or an answer.onidpassertionerror the rtcpeerconnection.onidpassertionerror event handler is a property containing the code to execute whent the idpassertionerror event, of type rtcidentityerrorevent, is received by this rtcpeerconnection. ...
...And 4 more matches

Using Web Workers - Web APIs
ed), not shared. read transferring data to and from workers: further details for a much more thorough explanation. terminating a worker if you need to immediately terminate a running worker from the main thread, you can do so by calling the worker's terminate method: myworker.terminate(); the worker thread is killed immediately. handling errors when a runtime error occurs in the worker, its onerror event handler is called. it receives an event named error which implements the errorevent interface. the event doesn't bubble and is cancelable; to prevent the default action from taking place, the worker can call the error event's preventdefault() method. the error event has the following three fields that are of interest: message a human-readable error message. filename the name of th...
...to call many different functions both on the main page and in the worker, you can create a system which groups everything together. ...
...r class that takes the url of the worker, a default listener, and an error handler, and this class is going to keep track of a list of listeners and help us communicate with the worker: function queryableworker(url, defaultlistener, onerror) { var instance = this, worker = new worker(url), listeners = {}; this.defaultlistener = defaultlistener || function() {}; if (onerror) {worker.onerror = onerror;} this.postmessage = function(message) { worker.postmessage(message); } this.terminate = function() { worker.terminate(); } } then we add the methods of adding/removing listeners: this.addlisteners = function(name, listener) { listeners[name] = listener; } this.removelisteners = function(name) { delete listeners[name]; } her...
...And 4 more matches

passwords - Archive of obsolete content
ter the url. so: if a web server at http://www.example.com requested authentication with a response code like this: http/1.0 401 authorization required server: apache/1.3.27 www-authenticate: basic realm="exampleco login" the corresponding values for the credential (excluding username and password) should be: url: "http://www.example.com" realm: "exampleco login" oncomplete and onerror this api is explicitly asynchronous, so all its functions take two callback functions as additional options: oncomplete and onerror. oncomplete is called when the operation has completed successfully and onerror is called when the function encounters an error. because the search function is expected to return a list of matching credentials, its oncomplete option is mandatory. because the other...
... globals functions search(options) this function is used to retrieve a credential, or a list of credentials, stored in the password manager. you pass it any subset of the possible properties a credential can contain. credentials which match all the properties you supplied are returned as an argument to the oncomplete callback. ...
...tring for http authentication credentials, the realm for which the credential was requested. for add-on credentials, a name for the credential. usernamefield string the value of the name attribute for the user name input field in a form. passwordfield string the value of the name attribute for the password input field in a form. onerror function the callback function that is called if the function failed. the callback is passed an error containing a reason of a failure: this is an nsiexception object. store(options) this function is used to store a credential in the password manager. it takes an options object as an argument: this contains all the properties for the new credential. as different sorts of ...
...And 3 more matches

Optional chaining (?.) - JavaScript
this position as well: someinterface?.custommethod?.() dealing with optional callbacks or event handlers if you use callbacks or fetch methods from an object with a destructuring assignment, you may have non-existent values that you cannot call as functions unless you have tested their existence. ...
...acks or event handlers if you use callbacks or fetch methods from an object with a destructuring assignment, you may have non-existent values that you cannot call as functions unless you have tested their existence. using ?., you can avoid this extra test: // written as of es2019 function dosomething(oncontent, onerror) { try { // ... ...
...f you use callbacks or fetch methods from an object with a destructuring assignment, you may have non-existent values that you cannot call as functions unless you have tested their existence. using ?., you can avoid this extra test: // written as of es2019 function dosomething(oncontent, onerror) { try { // ... ...
...And 3 more matches

constructor - JavaScript
provide your own constructor, then a default constructor will be supplied for you. ...
...constructor() {} if your class is a derived class, the default constructor calls the parent constructor, passing along any arguments that were provided: constructor(...args) { super(...args); } that enables code like this to work: class validationerror extends error { printcustomermessage() { return `validation failed :-( (details: ${this.message})`; } } try { throw new validationerror("not a valid phone number"); } catch (error) { if (error instanceof validationerror) { console.log(error.name); // this is error instead of validationerror! console.log(error.printcustomermessage()); } else { console.log('unknown error', error); throw error; } } the validationerror class doesn't need an explicit constructor, because it doesn't need to do any custom initial...
... class doesn't need an explicit constructor, because it doesn't need to do any custom initialization. the default constructor then takes care of initializing the parent error from the argument it is given. however, if you provide your own constructor, and your class derives from some parent class, then you must explicitly call the parent class constructor using super. ...
...And 2 more matches

JavaScript Debugger Service - Archive of obsolete content
ervice); jsd.on(); // enables the service till firefox 3.6, for 4.x use asyncon if (jsd.ison) jsd.off(); // disables the service hooks jsd operates using the events hook mechanism. next, we add code to the various hooks. ...
... jsd operates using the events hook mechanism. next, we add code to the various hooks. jsd.scripthook = { onscriptcreated: function(script) { // your function here }, onscriptdestroyed: function(script) { // your function here } }; jsd.errorhook = { onerror: function(message, filename, lineno, colno, flags, errnum, exc) { // your function here } }; // triggered when jsd.errorhook[onerror] returns false jsd.debughook = { onexecute: function(frame, type, rv) { // your function here } }; jsd.enumeratescripts({ // the enumeratescript method will be called once for every script jsd knows about enumeratescript: function(script) { // your function here } }); a simple stack trace here, we will show how to implement a simple javascript stack trace using the jsd. note that on...
...ame, type, rv) { // your function here } }; jsd.enumeratescripts({ // the enumeratescript method will be called once for every script jsd knows about enumeratescript: function(script) { // your function here } }); a simple stack trace here, we will show how to implement a simple javascript stack trace using the jsd. note that onerror is called for every exception. ...
...ort_warning) messagetype = "warning"; if (flags & jsdierrorhook.report_exception) messagetype = "uncaught-exception"; if (flags & jsdierrorhook.report_strict) messagetype += "-strict"; dump(messagetype + "\n"); return false; // trigger debughook // return true; if you do not wish to trigger debughook } }; // note that debughook does not _always_ trigger when jsd.errorhook[onerror] returns false // it is not well-known why debughook sometimes fails to trigger jsd.debughook = { onexecute: function(frame, type, rv) { stacktrace = ""; for (var f = frame; f; f = f.callingframe) { stacktrace += f.script.filename + "@" + f.line + "@" + f.functionname + "\n"; } dump(stacktrace); return components.interfaces.jsdiexecutionhook.return_continue; } }; filters jsd al...

Application cache implementation overview
st download”. if so, the update switches to downloading state and fetches in parallel items listed in the manifest by call to nsofflinecacheupdate::processnexturi(). if the new hash is identical, update invokes onnoupdate event and is 'finished'. then it associates any documents waiting for this update to finish with the current existing nsiapplicationcache. if the manifest load failed, onerror event is invoked and the update 'finishes'. the parallel load is implemented by asynchronous recursive calls to processnexturi(), a method searching always a single entry that is scheduled to load. when found, channel is open for it (+onprogress event is invoked). processnexturi then invokes it self asynchronously via dispatch to a main thread when not already on the concurrency limit of 15 l...
...cycle is stopped. from now on processnexturi can only be called from loadcompleted() again. note: the processnexturi method early returns when state of the update is different then downloading. on downloading state loadcompleted checks whether load of the item succeeded. if so, its marked as valid in the new cache version and processnexturi() is called. otherwise, the update invokes onerror and 'finishes'. when processnexturi discovers there are no more items to download it starts a “manifest check” implemented by nsmanifestcheck. nsmanifestcheck downloads the manifest from the server one more time and checks its content has not changed again. the results is passed to the original update via manifestcheckcompleted method. when the manifest is ...
...s is passed to the original update via manifestcheckcompleted method. when the manifest is identical, the cache is activated, onupdateready event is invoked and the update 'finishes'. when the manifest has changed, the update is simply rescheduled, with limit of up to 3 retries (then it fails.) when load of the manifest has failed or redirected, the original update invokes onerror and 'finishes'. on canceled state loadcompleted invokes onerror event and 'finishes' the update (what transits the state to finished). canceled can be set only by call to nsofflinecacheupdate::cancel() public method that also cancels all running items downloads immediately. on finished state loadcompleted just early returns. finished state is set when updated is 'f...
... the state to finished). ...

The Publicity Stream API
ll doable?] the javascript library should be included from: https://myapps.mozillalabs.com/jsapi/publicity.js all apis related to open web applications are accessed under the navigator.apps object. publicity stream api (navigator.apps.publicity.*) the publicity api is exposed as properties on the navigator.apps.publicity object. publicizeactivity( <activity>, [ { [ onsuccess: <function> ], [ onerror: <function> ] } ]): applications should call this method when an user-initiated activity deemed attractive to potential consumers occurs. this spawns a doorhanger which allows the user to specify which users can view the activity, and (following successful login and authorization with the stream server) registers the activity in a stream at [address]. this stream can be pulled down by getpublic...
...publicitystream() and helps determine the results for getuserrecommendedapps(). example use cases: 'adam got a high score in mafia wars', 'bethany bought a plane ticket to the caribbean', etc. activity is an object, formatted as per the fixme: deadlinkactivity streams open specification. onsuccess is a callback that will be invoked with no arguments if the activity is successfully posted. onerror is an error callback that will be invoked if the publicity fails. possible error codes include: denied - if the user refuses to publicize the activity permissiondenied - if the publicizing site is not allowed to post to the publicity stream networkerror - if the publicity server is unreachable activityparseerror - if the activity contains syntax errors (not proper json) invalida...
...server is unreachable activityparseerror - if the activity contains syntax errors (not proper json) invalidactivity - if the activity contains semantic errors (i.e. missing required properties) finally, the publicizeactivity() function will throw an exception if required arguments are missing, or if unsupported arguments are present. getpublicitystream( onsuccess: <function>, { [ onerror: <function> ], [ for_apps: <list> ], [ since: <date> ], [ before: <date> ], [ count: <int> ]): provides a means for a web store to receive a list of the current user's socially relevant app activity by being called from an origin which hosts a web store. it is not recommended that applications consume the publicity stream in any way (please use your own server for any in-app social aspects). it...
... way (please use your own server for any in-app social aspects). it is suggested that the list be processed and condensed into an attractive, cohesive format for users (eg., multiple tweets show as 'adam tweeted 4 times'). onsuccess will be called with a single argument: a json list of the current user's socially relevant app activity in the fixme: deadlinkactivity streams open specification. onerror is an error callback that will be invoked if the installation fails. possible error codes include: denied - if the user does not log in correctly permissiondenied - if the site is not allowed to access the publicity stream networkerror - if the publicity server is unreachable for_apps is a json list of apps that this store has (each represented as its origin url), so that stream ...

nsIDOMGeoGeolocation
hrows an exception when importing, try using this: var geolocation = components.classes["@mozilla.org/geolocation;1"] .getservice(components.interfaces.nsisupports); method overview void clearwatch(in unsigned short watchid); void getcurrentposition(in nsidomgeopositioncallback successcallback, [optional] in nsidomgeopositionerrorcallback errorcallback, [optional] in nsidomgeopositionoptions options); unsigned short watchposition(in nsidomgeopositioncallback successcallback, [optional] in nsidomgeopositionerrorcallback errorcallback, [optional] in nsidomgeopositionoptions options); attributes attribute ty...
...r. may be null. read only. methods clearwatch() when the clearwatch() method is called, the watch() process stops calling for new position identifiers and cease invoking callbacks. void clearwatch( in unsigned short watchid ); parameters none. getcurrentposition() acquires the user's current position via a new position object. ...
...lling for new position identifiers and cease invoking callbacks. void clearwatch( in unsigned short watchid ); parameters none. getcurrentposition() acquires the user's current position via a new position object. if this fails, errorcallback is invoked with an nsidomgeopositionerror argument. void getcurrentposition( in nsidomgeopositioncallback successcallback, [optional] in nsidomgeopositionerrorcallback errorcallback, [optional] in nsidomgeopositionoptions options ); parameters successcallback an nsidomgeopositioncallback to be called when the current position is available. errorcallback an nsidomgeopositionerrorcallback that is called if an error occurs while retrieving the position; this parameter is optional. options an nsidomgeopositionoptions object s...
...arameter is optional. options an nsidomgeopositionoptions object specifying options; this parameter is optional. watchposition() similar to getcurrentposition(), except it continues to call the callback with updated position information periodically until clearwatch() is called. unsigned short watchposition( in nsidomgeopositioncallback successcallback, [optional] in nsidomgeopositionerrorcallback errorcallback, [optional] in nsidomgeopositionoptions options ); parameters successcallback an nsidomgeopositioncallback that is to be called whenever new position information is available. errorcallback an nsidomgeopositionerrorcallback to call when an error occurs; this is an optional parameter. options an nsidomgeopositionoptions object specifying option...

DOMException - Web APIs
e: not_found_err) notsupportederror the operation is not supported. (legacy code value: 9 and legacy constant name: not_supported_err) invalidstateerror the object is in an invalid state. (legacy code value: 11 and legacy constant name: invalid_state_err) syntaxerror the string did not match the expected pattern. (legacy code value: 12 and legacy constant name: syntax_err) invalidmodificationerror the object cannot be modified in this way. (legacy code value: 13 and legacy constant name: invalid_modification_err) namespaceerror the operation is not allowed by namespaces in xml. (legacy code value: 14 and legacy constant name: namespace_err) invalidaccesserror the object does not support the operation or argument. (legacy code value: 15 and legacy constant name: invalid_access_err) ty...
... value and constant name). dataerror provided data is inadequate (no legacy code value and constant name). transactioninactiveerror a request was placed against a transaction that is currently not active or is finished (no legacy code value and constant name). readonlyerror the mutating operation was attempted in a "readonly" transaction (no legacy code value and constant name). versionerror an attempt was made to open a database using a lower version than the existing version (no legacy code value and constant name). operationerror the operation failed for an operation-specific reason (no legacy code value and constant name). notallowederror the request is not allowed by the user agent or the platform in the current context, possibly because the user denied permission (no l...
... ...
...ed permission (no legacy code value and constant name). specifications specification status comment web idlthe definition of 'constructor' in that specification. candidate recommendation adds the constructor for the domexception class. adds the notreadableerror, unknownerror, constrainterror, dataerror, transactioninactiveerror, readonlyerror, versionerror, operationerror, and notallowederror values. ...

FileHandle API - Web APIs
peration always writes content at the end of the file. truncate : this operation keeps the nth-first bytes of the file and removes the rest. // get a lockedfile object from the handle var myfile = myfilehandle.open('readwrite'); // start a writing operation var writing = myfile.append('some content'); writing.onsuccess = function () { console.log('writing operation successful'); } writing.onerror = function () { console.log('something goes wrong in the writing process: ' + this.error); } reading it's possible to directly write the content of a lockedfile object without using an intermediate file object and a filereader object. the lockedfile interface provides a readastext method and a readasarraybuffer method. those two methods expect a size to indicate how many bytes must be read ...
...for example, there are many apis that expect blob or file objects such as filereader (which can be easier to use to read the whole file) or xmlhttprequest. it's possible to get a file object representing the current sta...
...if you want a file to survive a page refresh/app relaunch, you need to store the handle in a database (not necessarily the one used to create the filehandle object). var idbreq = wind...
...ill be safe. // get a lockedfile object from the handle var myfile = myfilehandle.open('readwrite'); // start a writing operation var writing = myfile.append('some content'); writing.onsuccess = function () { console.log('writing operation successful'); var saving = myfile.flush(); saving.onsuccess = function () { console.log('the file has been successfully stored'); } } writing.onerror = function () { console.log('something goes wrong in the writing process: ' + this.error); } api compatibility why a different api than filewriter? the filewriter specification defines filewriters, objects aiming at representing editable files. discussions on public-webapps led to the conclusion that the api would behave poorly in the case of different entities writing concurrently to the sa...

IDBDatabase - Web APIs
neventname property of this interface. abort fired when when a transaction is aborted and bubbles up to the connection object. also available via the onabort property. close fired when the database connection is unexpectedly closed. also available via the onclose property. error fired when a request returns an error and the event bubbles up to the connection object. also available via the onerror property. versionchange fired when a database structure change was requested. also available via the onversionchange property. example in the following code snippet, we open a database asynchronously (idbfactory), handle success and error cases, and create a new object store in the case that an upgrade is needed (idbdatabase). for a complete working example, see our to-do notifications app (...
...s and error cases, and create a new object store in the case that an upgrade is needed (idbdatabase). for a complete working example, see our to-do notifications app (view example live.) // let us open our database var dbopenrequest = window.indexeddb.open("todolist", 4); // these two event handlers act on the idbdatabase object, // when the database is opened successfully, or not dbopenrequest.onerror = function(event) { note.innerhtml += '<li>error loading database.</li>'; }; dbopenrequest.onsuccess = function(event) { note.innerhtml += '<li>database initialised.</li>'; // store the result of opening the database in the db // variable. this is used a lot later on db = dbopenrequest.result; // run the displaydata() function to populate the task // list with all the to-do list ...
...the task // list with all the to-do list data already in the idb displaydata(); }; // this event handles the event whereby a new version of // the database needs to be created either one has not // been created before, or a new version number has been // submitted via the window.indexeddb.open line above dbopenrequest.onupgradeneeded = function(event) { var db = event.target.result; db.onerror = function(event) { note.innerhtml += '<li>error loading database.</li>'; }; // create an objectstore for this database using // idbdatabase.createobjectstore var objectstore = db.createobjectstore("todolist", { keypath: "tasktitle" }); // define what data items the objectstore will contain objectstore.createindex("hours", "hours", { unique: false }); objectstore.createindex...
... yeschrome android full support 31firefox android full support 50opera android full support yessafari ios full support 10.3samsung internet android full support 2.0onerrorchrome full support 24 full support 24 no support 23 — 24prefixed prefixed implemented with the vendor prefix: webkitedge full support 12firefox full support 16 full support ...

IDBRequest: error event - Web APIs
the error handler is executed when an error caused a request to fail. ...
...rror examples this example opens a database and tries to add a record, listening for the error event for the add() operation (this will occur if, for example, a record with the given tasktitle already exists): // open the database const dbopenrequest = window.indexeddb.open('todolist', 4); dbopenrequest.addeventlistener('upgradeneeded', event => { const db = event.target.result; db.onerror = () => { console.log('error creating database'); }; // create an objectstore for this database var objectstore = db.createobjectstore('todolist', { keypath: 'tasktitle' }); // define what data items the objectstore will contain objectstore.createindex('hours', 'hours', { unique: false }); objectstore.createindex('minutes', 'minutes', { unique: false }); objectstore.createinde...
...t'], 'readwrite'); const objectstore = transaction.objectstore('todolist'); const newitem = { tasktitle: 'my task', hours: 10, minutes: 10, day: 10, month: 'january', year: 2020 }; const objectstorerequest = objectstore.add(newitem); objectstorerequest.addeventlistener('error', () => { console.log(`error adding new item: ${newitem.tasktitle}`); }); }); the same example, using the onerror property instead of addeventlistener(): // open the database const dbopenrequest = window.indexeddb.open('todolist', 4); dbopenrequest.onupgradeneeded = event => { const db = event.target.result; db.onerror = () => { console.log('error creating database'); }; // create an objectstore for this database var objectstore = db.createobjectstore('todolist', { keypath: 'tasktitle' }); ...
...b = dbopenrequest.result; // open a read/write db transaction, ready for adding the data const transaction = db.transaction(['todolist'], 'readwrite'); const objectstore = transaction.objectstore('todolist'); const newitem = { tasktitle: 'my task', hours: 10, minutes: 10, day: 10, month: 'january', year: 2020 }; const objectstorerequest = objectstore.add(newitem); objectstorerequest.onerror = () => { console.log(`error adding new item: ${newitem.tasktitle}`); }; }; ...

SpeechRecognition: error event - Web APIs
the error event of the web speech api speechrecognition object is fired when a speech recognition error occurs. ...
... the error event of the web speech api speechrecognition object is fired when a speech recognition error occurs. ...
... draft ...
...nitionerrorevent event handler property onerror examples you can use the error event in an addeventlistener method: var recognition = new webkitspeechrecognition() || new speechrecognition(); recognition.addeventlistener('error', function(event) { console.log('speech recognition error detected: ' + event.error'); }); or use the onerror event handler property: recognition.onerror = function(event) { console.log('speech recognition error detected: ' + event.error'); } specifications specification status comment web speech apithe definition of 'speech recognition events' in that specification. draft ...

Promises - Archive of obsolete content
r promises, its standard usage is very easy to adapt to a promise-based approach. moreover, many third-party wrappers for the xmlhttprequest api now support promises out of the box. example direct usage task.spawn(function* () { // make the initial request. let resp = yield new promise((resolve, reject) => { let xhr = new xmlhttprequest; xhr.onload = resolve; xhr.onerror = reject; xhr.open("get", dataurl); xhr.responsetype = "json"; xhr.send(); }); let data = resp.target.response; // use the response to construct form data object for the // second request. let form = new formdata; form.append("id", data.id); form.append("content", data.content); // make the second request. resp = yield new promise((re...
... }); let data = resp.target.response; // use the response to construct form data object for the // second request. let form = new formdata; form.append("id", data.id); form.append("content", data.content); // make the second request. resp = yield new promise((resolve, reject) => { let xhr = new xmlhttprequest; xhr.onload = resolve; xhr.onerror = reject; xhr.open("post", updateurl); xhr.send(form); }); // use the response of the second request. notifyuser(resp.target.responsetext); }); example using promise-based helper the following example relies on the helper function defined below. task.spawn(function* () { // make the initial request. let xhr = yield request(dataurl, { responsetype: "json" })...
..."post" : "get"; if (options.mimetype) xhr.overridemimetype(params.options); xhr.open(options.method || defaultmethod, url); if (options.responsetype) xhr.responsetype = options.responsetype; for (let header of object.keys(options.headers || {})) xhr.setrequestheader(header...

Client-side storage - Learn web development
e your database (for example, by changing the table structure), you have to run your code again with an increased version number, different schema specified inside the onupgradeneeded handler (see below), etc. we won't cover upgrading databases in this simple tutorial. now add the following event handlers just below your previous addition — again inside the window.onload handler: // onerror handler signifies that the database didn't open successfully request.onerror = function() { console.log('database failed to open'); }; // onsuccess handler signifies that the database opened successfully request.onsuccess = function() { console.log('database opened successfully'); // store the opened database object in the db variable. this is used a lot below db = request.result; //...
...'database failed to open'); }; // onsuccess handler signifies that the database opened successfully request.onsuccess = function() { console.log('database opened successfully'); // store the opened database object in the db variable. this is used a lot below db = request.result; // run the displaydata() function to display the notes already in the idb displaydata(); }; the request.onerror handler will run if the system comes back saying that the request failed. this allows you to respond to this problem. in our simple example, we just print a message to the javascript console. the request.onsuccess handler on the other hand will run if the request returns successfully, meaning the database was successfully opened. if this is the case, an object representing the opened database ...
...t entry titleinput.value = ''; bodyinput.value = ''; }; // report on the success of the transaction completing, when everything is done transaction.oncomplete = function() { console.log('transaction completed: database modification finished.'); // update the display of data to show the newly added item, by running displaydata() again. displaydata(); }; transaction.onerror = function() { console.log('transaction not opened due to error'); }; } this is quite complex; breaking it down, we: run event.preventdefault() on the event object to stop the form actually submitting in the conventional manner (this would cause a page refresh and spoil the experience). create an object representing a record to enter into the database, populating it with values from th...

IDBDatabase: error event - Web APIs
the error event is fired on idbdatabase when a request returns an error and the event bubbles up to the connection object. ...
...est.result; db.addeventlistener('error', () => { console.log(`error adding new item: ${newitem.tasktitle}`); }); // open a read/write db transaction, ready for adding the data const transaction = db.transaction(['todolist'], 'readwrite'); const objectstore = transaction.objectstore('todolist'); const objectstorerequest = objectstore.add(newitem); }; the same example, using the onerror property instead of addeventlistener(): // open the database const dbopenrequest = window.indexeddb.open('todolist', 4); dbopenrequest.onupgradeneeded = (event) => { const db = event.target.result; // create an objectstore for this database const objectstore = db.createobjectstore('todolist', { keypath: 'tasktitle' }); // define what data items the objectstore will contain objectsto...
...', { unique: false }); objectstore.createindex('day', 'day', { unique: false }); objectstore.createindex('month', 'month', { unique: false }); objectstore.createindex('year', 'year', { unique: false }); }; dbopenrequest.onsuccess = (event) => { const newitem = { tasktitle: 'my task', hours: 10, minutes: 10, day: 10, month: 'january', year: 2020 }; const db = dbopenrequest.result; db.onerror = () => { console.log(`error adding new item: ${newitem.tasktitle}`); }; // open a read/write db transaction, ready for adding the data const transaction = db.transaction(['todolist'], 'readwrite'); const objectstore = transaction.objectstore('todolist'); const objectstorerequest = objectstore.add(newitem); }; ...

IDBRequest.error - Web APIs
his error, for example, if you try to add a new key that already exists in the record. quotaexceedederror if you run out of disk quota and the user declined to grant you more space. unknownerror if the operation failed for reasons unrelated to the database itself. a failure due to disk io errors is such an example. noerror if the request succeeds. versionerror if you try to open a database with a version lower than the one it already has. in addition to the error codes sent to the idbrequest object, asynchronous operations can also raise exceptions. the list describes problems that could occur when the request is being executed, but you might also encounter other problems when the request is being made. for example, if the the request failed ...
...e request failed and the result is not available, the invalidstateerror exception is thrown. example the following example requests a given record title, onsuccess gets the associated record from the idbobjectstore (made available as objectstoretitlerequest.result), updates one property of the record, and then puts the updated record back into the object store. also included at the bottom is an onerror function that reports what the error was if the request fails. for a full working example, see our to-do notifications app (view example live.) var title = "walk dog"; // open up a transaction as usual var objectstore = db.transaction(['todolist'], "readwrite").objectstore('todolist'); // get the do-do list with the specified title var objectstoretitlerequest = objectstore.get(title); objects...
... recommendation indexed database api draftthe definition of 'er...

IDBRequest - Web APIs
plain words, all asynchronous methods return a request object. if the request has been completed successfully, the result is made available through the result property and an event indicating success is fired at the request (idbrequest.onsuccess). if an error occurs while performing the operation, the exception is made available through the result property and an error event is fired (idbrequest.onerror). the interface idbopendbrequest is derived from idbrequest. note: this feature is available in web workers. <div id="interfacediagram" style="display: inline-block; position: relative; width: 100%; padding-bottom: 11.666666666666666%; vertical-align: middle; overflow: hidden;"><svg style="display: inline-block; position: absolute; top: 0; left: 0;" viewbox="-50 0 600 70" preserveaspectrat...
...factory.open unless an upgrade is needed. (you're just connecting to a database, so there is no transaction to return). methods no methods, but inherits methods from eventtarget. events listen to these events using addeventlistener() or by assigning an event listener to the oneventname property of this interface. error fired when an error caused a request to fail. also available via the onerror property. success fired when an idbrequest succeeds. also available via the onsuccess property. example in the following code snippet, we open a database asynchronously and make a request; onerror and onsuccess functions are included to handle the success and error cases. for a full working example, see our to-do notifications app (view example live.) var db; // let us open our database v...
...ase asynchronously and make a request; onerror and onsuccess functions are included to handle the success and error cases. for a full working example, see our to-do notifications app (view example live.) var db; // let us open our database var dbopenrequest = window.indexeddb.open("todolist", 4); // these two event handlers act on the database being // opened successfully, or not dbopenrequest.onerror = function(event) { note.innerhtml += '<li>error loading database.</li>'; }; dbopenrequest.onsuccess = function(event) { note.innerhtml += '<li>database initialised.</li>'; // store the result of opening the database. db = dbopenrequest.result; }; specifications specification status comment indexed database api 2.0the definition of 'idbrequest' in that specific...

IDBTransaction: error event - Web APIs
the error event is fired on idbtransaction when a request returns an error and the event bubbles up to the transaction object. ...
...odolist'], 'readwrite'); transaction.addeventlistener('error', () => { console.log(`error adding new item: ${newitem.tasktitle}`); }); const objectstore = transaction.objectstore('todolist'); const newitem = { tasktitle: 'my task', hours: 10, minutes: 10, day: 10, month: 'january', year: 2020 }; const objectstorerequest = objectstore.add(newitem); }; the same example, using the onerror property instead of addeventlistener(): // open the database const dbopenrequest = window.indexeddb.open('todolist', 4); dbopenrequest.onupgradeneeded = (event) => { const db = event.target.result; // create an objectstore for this database const objectstore = db.createobjectstore('todolist', { keypath: 'tasktitle' }); // define what data items the objectstore will contain objectsto...
...ore.createindex('day', 'day', { unique: false }); objectstore.createindex('month', 'month', { unique: false }); objectstore.createindex('year', 'year', { unique: false }); }; dbopenrequest.onsuccess = (event) => { const db = dbopenrequest.result; // open a read/write db transaction, ready for adding the data const transaction = db.transaction(['todolist'], 'readwrite'); transaction.onerror = () => { console.log(`error adding new item: ${newitem.tasktitle}`); }; const objectstore = transaction.objectstore('todolist'); const newitem = { tasktitle: 'my task', hours: 10, minutes: 10, day: 10, month: 'january', year: 2020 }; const objectstorerequest = objectstore.add(newitem); }; ...

IDBTransaction - Web APIs
signing an event listener to the oneventname property of this interface. abort fired when an indexeddb transaction is aborted. also available via the onabort property. complete fired when a transaction successfully completes. also available via the oncomplete property. error fired when a request returns an error and the event bubbles up to the transaction object. also available via the onerror property. mode constants these constants are no longer available — they were removed in gecko 25. you should use the string constants directly instead. (bug 888598) transactions can have one of three modes: constant value description read_only "readonly" (0 in chrome) allows data to be read but not changed. read_write...
...duplicate items not allowed.</li>'; }; // create an object store on the transaction var objectstore = transaction.objectstore("todolist"); // add our newitem object to the object store var objectstorerequest = objectstore.add(newitem[0]); objectstorerequest.onsuccess = function(event) { // report ...
... yeschrome android full support yesfirefox android full support 22opera android full support 14safari ios full support 8samsung internet android full support yesonerrorchrome full support 24 full support 24 full support 23prefixed prefixed implemented with the vendor prefix: webkitedge full support 12firefox full support 16 f...

RTCPeerConnection.setRemoteDescription() - Web APIs
rror the rtcpeerconnection is closed, or it's in a state which isn't compatible with the specified description's type. for example, if the type is rollback and the signaling state is one of stable, have-local-pranswer, or have-remote-pranswer, this exception is thrown, because you can't roll back a connection that's either fully established or is in the final stage of becoming connected. operationerror any errors that occur which don't match the others specifeid here are reported as operationerror. this includes identity validation errors. rtcerror an rtcerror with the errordetail set to sdp-syntax-error is reported if the sdp specified by rtcsessiondescription.sdp. the error object's sdplinenumber property indicates the line number within the sdp on which the syntax error was detected. typ...
...dating existing code. pc.setremotedescription(sessiondescription, successcallback, errorcallback); parameters successcallback a javascript function which accepts no input parameters to be be called once the description has been successfully set. at that time, the offer can be sent to a remote peer via the signaling server. errorcallback a function matching the signautre rtcpeerconnectionerrorcallback which gets called if the description can't be set. it is passed a single domexception object explaining why the request failed. this deprecated form of the method returns instantaneously without waiting for the actual setting to be done: in case of success, the successcallback will be called; in case of failure, the errorcallback will be called. exceptions when using the deprecated ca...
...ss, the successcallback will be called; in case of failure, the errorcallback will be called. exceptions when using the deprecated callback-based version of setremotedescription(), the following exceptions may occur: invalidstateerror the connection's signalingstate is "closed", indicating that the connection is not currently open, so negotiation cannot take place. invalidsessiondescriptionerror the rtcsessiondescription specified by the sessiondescription parameter is invalid. example here we see a function which handles an offer received from the remote peer. this code is derived from the example and tutorial in the article signaling and video calling; take a look at that for more details and a more in-depth explanation of what's going on. function handleoffer(msg) { createmyp...

Using the Web Speech API - Web APIs
ch was recognised that wasn't in the defined grammar, or an error occured. ...
... the web speech api has...
... the web speech api has a main controller interface for this — speechsynthesis — plus a num...

XMLHttpRequest: error event - Web APIs
the error event is fired when the request encountered an error. ...
...ut class="xhr abort" type="button" name="xhr" value="click to start xhr (abort)" /> </div> <textarea readonly class="event-log"></textarea> css .event-log { width: 25rem; height: 4rem; border: 1px solid black; margin: .5rem; padding: .2rem; } input { width: 11rem; margin: .5rem; } js const xhrbuttonsuccess = document.queryselector('.xhr.success'); const xhrbuttonerror = document.queryselector('.xhr.error'); const xhrbuttonabort = document.queryselector('.xhr.abort'); const log = document.queryselector('.event-log'); function handleevent(e) { log.textcontent = log.textcontent + `${e.type}: ${e.loaded} bytes transferred\n`; } function addlisteners(xhr) { xhr.addeventlistener('loadstart', handleevent); xhr.addeventlistener('load', handleevent); ...
...deventlistener('error', handleevent); xhr.addeventlistener('abort', handleevent); } function runxhr(url) { log.textcontent = ''; const xhr = new xmlhttprequest(); addlisteners(xhr); xhr.open("get", url); xhr.send(); return xhr; } xhrbuttonsuccess.addeventlistener('click', () => { runxhr('https://mdn.mozillademos.org/files/16553/dgszyjnxcaipwzy.jpg'); }); xhrbuttonerror.addeventlistener('click', () => { runxhr('https://somewhere.org/i-dont-exist'); }); xhrbuttonabort.addeventlistener('click', () => { runxhr('https://mdn.mozillademos.org/files/16553/dgszyjnxcaipwzy.jpg').abort(); }); result specifications specification status comment xmlhttprequest living standard ...

Web APIs
rectoryentry filesystemdirectoryreader filesystementry filesystementrysync filesystemfileentry filesystemflags filesystemsync focusevent fontface fontfaceset fontfacesetloadevent formdata formdataentryvalue formdataevent fullscreenoptions g gainnode gamepad gamepadbutton gamepadevent gamepadhapticactuator geolocation geolocationcoordinates geolocationposition geolocationpositionerror geometryutils gestureevent globaleventhandlers gyroscope h htmlanchorelement htmlareaelement htmlaudioelement htmlbrelement htmlbaseelement htmlbasefontelement htmlbodyelement htmlbuttonelement htmlcanvaselement htmlcollection htmlcontentelement htmldlistelement htmldataelement htmldatalistelement htmldetailselement htmldialogelement htmldivelement htmldocument htmlelement htmlembedele...
...flineaudiocontext offscreencanvas orientationsensor oscillatornode overconstrainederror p pagetransitionevent paintworklet pannernode parentnode passwordcredential path2d payererrors paymentaddress paymentcurrencyamount paymentdetailsbase paymentdetailsupdate paymentitem paymentmethodchangeevent paymentrequest paymentrequestevent paymentrequestupdateevent paymentresponse paymentvalidationerrors pbkdf2params performance performanceentry performanceeventtiming performanceframetiming performancelongtasktiming performancemark performancemeasure performancenavigation performancenavigationtiming performanceobserver performanceobserverentrylist performancepainttiming performanceresourcetiming performanceservertiming performancetiming periodicwave permissionstatus permissions photocapa...
...s securitypolicyviolationevent selection sensor sensorerrorevent serviceworker serviceworkercontainer serviceworkerglobalscope serviceworkermessageevent serviceworkerregistration serviceworkerstate shadowroot sharedworker sharedworkerglobalscope slottable sourcebuffer sourcebufferlist speechgrammar speechgrammarlist speechrecognition speechrecognitionalternative speechrecognitionerror speechrecognitionerrorevent speechrecognitionevent speechrecognitionresult speechrecognitionresultlist speechsynthesis speechsynthesiserrorevent speechsynthesisevent speechsynthesisutterance speechsynthesisvoice staticrange stereopannernode storage storageestimate storageevent storagemanager storagequota stylepropertymap stylepropertymapreadonly stylesheet stylesheetlist s...

Audio and Video Delivery - Developer guides
mediastream recording new standards are being rolled out to allow your browser to grab media from your mic or camera using getusermedia ...
... mediarecorder object, take the resulting output and feed it to your audio or video source*. ...
... media source extensions (mse) media source extensions is a w3c working draft that plans to extend htmlmediaelement to allow javascript to generate media streams for playback. ...

Caching compiled WebAssembly modules - WebAssembly
st helper function contained inside instantiatecachedurl() — opendatabase() — creates an object store for storing wasm modules, and also handles clearing out the database if the dbversion is updated; it returns a promise resolving to the new database. ...
...upindatabase() — provides a simple promise-based operation for looking up the given url in the object store we created above. it resolves with the stored compiled module, or rejects with an error. ...
...${url} was not found in wasm cache`); } }); } storing and instantiating modules next, we define a function storeindatabase() that fires off an async operation to store a given wasm module in a given database. function storeindatabase(db, module) { var store = db.transaction([storename], 'readwrite').objectstore(storename); var request = store.put(module, url); request.onerror = err => { console.log(`failed to store in wasm cache: ${err}`) }; request.onsuccess = err => { console.log(`successfully stored ${url} in wasm cache`) }; } using our helper functions with all the promise-based helper functions defined, we can now express the core logic of an indexeddb cache lookup. we start by trying to open a database, then see if we already have a compiled module with ...

Connecting to Remote Content - Archive of obsolete content
json, html and plain text. in this section we'll look into the xml and json communication mechanisms. let url = "http://www.example.com/"; let request = components.classes["@mozilla.org/xmlextras/xmlhttprequest;1"] .createinstance(components.interfaces.nsixmlhttprequest); request.onload = function(aevent) { window.alert("response text: " + aevent.target.responsetext); }; request.onerror = function(aevent) { window.alert("error status: " + aevent.target.status); }; request.open("get", url, true); request.send(null); in this example we demonstrate how to make a xmlhttprequest call in asynchronous mode. you can see that an instance of the xmlhttprequest class is created and it holds all functionality for making a request. we create this instance using xpcom instead of the usua...
...d(null); in this example we demonstrate how to make a xmlhttprequest call in asynchronous mode. you can see that an instance of the xmlhttprequest class is created and it holds all functionality for making a request. we create this instance using xpcom instead of the usual way (new xmlhttprequest()) because this way works both in chrome and non-chrome code. following initialization, onload and onerror handlers are registered to a callback function to handle the response returned from the remote server. in both cases aevent.target is an nsixmlhttprequest. in the onload callback function, the responsetext parameter contains the server response as text. if the response is an xml document, the responsexml property will hold an xmldocument object that can be manipulated using dom methods. sometime...

Monitoring WiFi access points - Archive of obsolete content
netscape.security.privilegemanager.enableprivilege('universalxpconnect'); var d = document.getelementbyid("d"); d.innerhtml = ""; for (var i=0; i<accesspoints.length; i++) { var a = accesspoints[i]; d.innerhtml += "<p>" + a.mac + " " + a.ssid + " " + a.signal + "</p>"; } var c = document.getelementbyid("c"); c.innerhtml = "<p>" + count++ + "</p>"; }, onerror: function (value) { alert("error: " +value); }, queryinterface: function(iid) { netscape.security.privilegemanager.enableprivilege('universalxpconnect'); if (iid.equals(components.interfaces.nsiwifilistener) || iid.equals(components.interfaces.nsisupports)) return this; throw components.results.ns_error_no_interface; }, } netscape.se...
... onchange() method (lines 13 through 27) begins by enabling universalxpconnect privileges, then clearing out the div (d) that will receive the updated list of access points. then the loop in lines 19-22 iterates over the list of access points received in the accesspoints array and adds them to the html in the div. then the c div is updated with the number of times the list has been refreshed. the onerror() method simply opens an alert that displays the error code received. starting to monitor access points to start monitoring the access points, we instantiate the listener (on line 44), then get access to the wifi monitor interface on line 45. the monitoring is started up on line 47, by calling the wifi monitoring service's startwatching() method. ...

Textbox (XPFE autocomplete) - Archive of obsolete content
search, autocompletesearchparam, autofill, autofillaftermatch, autofill, completedefaultindex, crop, disableautocomplete, disableautocomplete, disabled, disablehistory, enablehistory, focused, forcecomplete, forcecomplete, highlightnonmatches, ignoreblurwhilesearching, ignoreblurwhilesearching, inputtooltiptext, label, maxlength, maxrows, minresultsforpopup, minresultsforpopup, nomatch, onchange, onerrorcommand, oninput, onsearchcomplete, ontextcommand, ontextentered, ontextrevert, ontextreverted, open, readonly, searchsessions, showcommentcolumn, showcommentcolumn, showpopup, size, tabindex, tabscrolling, tabscrolling, timeout, type, useraction, value properties accessible, alwaysopenpopup, autofill, autofillaftermatch, completedefaultindex, crop, disableautocomplete, disabled, e...
... oninput type: script code this event is sent when a user enters text in a textbox. this event is only called when the text displayed would change, thus it is not called when the user presses non-displayable keys. onsearchcomplete new in thunderbird 3requires seamo...

Browser Feature Detection - Archive of obsolete content
le cellspacing="0">'); for (i = 0; i < features.length; i++) { if (features[i].supported) document.write('<tr><td>' + features[i].name + '<\/td><td>' + features[i].supported + '<\/td><\/tr>'); else document.write('<tr><td>' + features[i].name + '<\/td><td style="background-color:red">' + features[i].supported + '<\/td><\/tr>'); } document.write('<\/table>'); } var oldonerror = window.onerror; // suppress error messages... window.onerror = null; document.write('<p><b> your browser ' + navigator.useragent + '<\/b><\/p>'); generatereport(document, 'domcore1', 'document'); generatereport(document, 'domcore2', 'document'); generatereport(document, 'domhtml', 'document'); generatereport(document.body.style, 'domcss1', 'document.body.style'); generatereport(document...
...onerror = null; document.write('<p><b> your browser ' + navigator.useragent + '<\/b><\/p>'); generatereport(document, 'domcore1', 'document'); generatereport(document, 'domcore2', 'document'); generatereport(document, 'domhtml', 'document'); generatereport(document.body.style, 'domcss1', 'document.body.style'); generatereport(document.body.style, 'domcss2', 'document.body.style'); window.onerror = oldonerror; see also browser detection and cross browser support comparison of layout engines web specifications supported in opera 9 what's new in internet explorer 7 (script) original document information author(s): (unknown) last updated date: updated march 16, 2003 copyright information: copyright © 2001-2003 netscape. note: this reprinted article was originally part of the...

HTMLIFrameElement.download()
warning: removed in firefox 65. the download() method of the htmliframeelement interface downloads a specified url, storing it at /sdcard/download. syntax var instanceofdomrequest = instanceofhtmliframeelement.download(url, options); returns a domrequest for handling the download request. its request.onsuccess handler handles the success case, and its request.onerror handler handles the failure case. parameters url the url of the file to be downloaded. options optional an options object allowing optional settings to be specified for the download. the available options are: filename: the filename to save the downloaded file as. if this is not specified, the filename used will be the original filename, as specified in the url. referrer: specifies a referrer for the downloaded f...
...cified, the filename used will be the original filename, as specified in the url. referrer: specifies a referrer for the downloaded file. if this is not specified there will be no referrer. examples var browser = document.queryselector('iframe'); var request = browser.download(foourl, { filename: 'foo.bin' }); request.onsuccess = function() { console.log("file downladed"); } request.onerror = function() { console.log("download error"); } specification not part of any specification. ...

HTMLIFrameElement.getContentDimensions()
eelement interface retrieves the x and y dimensions of the content window. note: the values returned are equivalent to document.body.scrollwidth and document.body.scrollheight. syntax var instanceofdomrequest = instanceofhtmliframeelement.getcontentdimensions(); returns a domrequest for handling the dimensions request. its request.onsuccess handler handles the success case, and its request.onerror handler handles the failure case. the x and y dimensions are available in the request.result.x and request.result.y properties, respectively. parameters none. examples var browser = document.queryselector('iframe'); var request = browser.getcontentdimensions(); request.onsuccess = function() { console.log("page size:", request.result.width + "x" + request.result.height); } ...
...handles the failure case. the x and y dimensions are available in the request.result.x and request.result.y properties, respectively. parameters none. examples var browser = document.queryselector('iframe'); var request = browser.getcontentdimensions(); request.onsuccess = function() { console.log("page size:", request.result.width + "x" + request.result.height); } request.onerror = function() { console.log("download error"); } specification not part of any specification. ...

HTMLIFrameElement.purgeHistory()
elete cookies for a firefox os app, you could call clearbrowserdata() on the actual app itself. syntax there is a domrequest version and a promise version: var mydomrequest = instanceofhtmliframeelement.purgehistory(); instanceofhtmliframeelement.purgehistory().then(function() { ... ...
...object that returns an onsuccess handler if the history is deleted, or an onerror handler if not. a promise that resolves, with no parameters, if the history is deleted, or rejects if not. parameters none. examples domrequest: var browser = document.queryselector('iframe'); var request = browser.purgehistory(); request.onsuccess = function() { console.log('history deleted!'); } request.onerror = function() { console.error(this.error.name); } promise: var browser = document.queryselector('iframe'); browser.purgehistory().then(function() { console.log('history deleted!'); }, function(error) { console.error(this.error.name); }); specification not part of any specification. ...

Assert.jsm
undefined less(lhs, rhs, message); undefined lessorequal(lhs, rhs, message); undefined setreporter(reporterfunc); undefined report(failed, actual, expected, message, operator); constructor creates a new assert object. let assert = new assert(reporterfunc); the new assert instance, assert, uses reporterfunc to report assertion results or throws an assertionerror when an assertion fails, as default behavior. ok, equal, notequal, deepequal, notdeepequal, strictequal, notstrictequal, throws, setreporter, report methods ok() pure assertion tests whether a value is truthy, as determined by !!guard. this statement is equivalent to assert.equal(true, !!guard, message_opt);. to test strictly for the value true, use assert.strictequal(true, guard, message_op...
...ndler function. undefined setreporter( reporterfunc ); parameters reporterfunc reporter handler function. arguments passed in to this function are: err an error object when the assertion failed or null when it passed message message describing the assertion stack stack trace of the assertion function. report() all of the aforementioned functions must throw an assertionerror when a corresponding condition is not met, with a message that may be undefined if not provided. all assertion methods provide both the actual and expected values to the assertion error for display purposes. this report method only throws errors on assertion failures, as per spec, but consumers of this module (think: xpcshell-test, mochitest) may want to override this default implementation. ...

L20n Javascript API
xisting translations are buggy. the error object is passed as the first argument to callback. these errors include: context.runtimeerror, when an entity is missing or broken in all supported locales; in this case, l20n will show the the best available fallback of the requested entity in the ui: the source string as found in the resource, or the identifier. context.translationerror, when the translation is present but broken in one of supported locales; the context instance will try to retrieve a fallback translation from the next locale in the fallback chain, parser.error, when l20n is unable to parse the syntax of a resource; this might result in entities being broken which in turn can lead to above error being emitted. warning - fired when a less...
...the context instance can recover gracefully and try to fetch a translations from a fallback locale. the error object is passed as the first argument to callback and can be one of the following: context.error, when there are problems with setting up resources (e.g. ...

JS_SetErrorReporter
reporting function. you can work around this by using the js_setruntimeprivate and js_getruntimeprivate methods. ...
...} void onerror(const std::string& error) { // handle error } static void dispatcherror( jscontext* ctx, const char* message, jserrorreport* report) { auto rt = js_getruntime(ctx); auto rt_userdata = js_getruntimeprivate(rt); if (rt_userdata) { auto req = static_cast<myrequest*>(rt_userdata); req->onerror(message); } } }; see also mxr id search for js_geterrorreporter mxr id search for js_seterrorreporter bug 1277278 - js_seterrorreporter is renamed to js::setwarningreporter ...

Index
position information is available. you need to implement this interface to accept callbacks after using nsidomgeolocation.watchposition(). 490 nsidomgeopositioncoords dom, geolocation, interfaces, interfaces:scriptable, xpcom, xpcom api reference, xpcom interface reference the nsidomgeopositioncoords interface describes a geographical location. ...
....watchposition(). 490 nsidomgeopositioncoords dom, geolocation, interfaces, interfaces:scriptable, xpcom, xpcom api reference, xpcom interface reference the nsidomgeopositioncoords interface describes a geographical location. 491 nsidomgeopositionerror dom, geolocation, interfaces, interfaces:scriptable, xpcom, xpcom interface reference the nsidomgeopositionerror interface represents an error that occurred while performing geolocation operations. 492 nsidomgeopositionerrorcallback dom, geolocation, interfaces, interfaces:scriptable, xpcom, xpcom interface reference the nsidomgeopositionerrorcallback interface is used to represent an object that receives callback notifications when geolocation errors occur. 493 nsidomgeoposi...

nsIMicrosummaryObserver
es. 1.0 66 introduced gecko 1.8 obsolete gecko 6.0 inherits from: nsisupports last changed in gecko 1.9 (firefox 3) warning: microsummary support was removed in gecko 6.0 (firefox 6.0 / thunderbird 6.0 / seamonkey 2.3) method overview void oncontentloaded(in nsimicrosummary microsummary); void onelementappended(in nsimicrosummary microsummary); void onerror(in nsimicrosummary microsummary); methods oncontentloaded() called when an observed microsummary updates its content. since an observer might watch multiple microsummaries at the same time, the microsummary whose content has been updated gets passed to this handler. void oncontentloaded( in nsimicrosummary microsummary ); parameters microsummary the microsummary whose content has just bee...
...updated gets passed to this handler. void oncontentloaded( in nsimicrosummary microsummary ); parameters microsummary the microsummary whose content has just been updated. onelementappended() called when an element is appended to a microsummary set. void onelementappended( in nsimicrosummary microsummary ); parameters microsummary the microsummary that has just been appended to the set. onerror() called when an observed microsummary encounters an error during an update. void onerror( in nsimicrosummary microsummary ); parameters microsummary the microsumary which could not be updated. see also microsummary topics creating a microsummary ...

nsIUpdateCheckListener
ation. this object is notified as the check continues, finishes and if it has an error. 1.0 66 introduced gecko 1.8 inherits from: nsisupports last changed in gecko 1.8 (firefox 1.5 / thunderbird 1.5 / seamonkey 1.0) method overview void oncheckcomplete(in nsixmlhttprequest request, [array, size_is(updatecount)] in nsiupdate updates, in unsigned long updatecount); void onerror(in nsixmlhttprequest request, in nsiupdate update); void onprogress(in nsixmlhttprequest request, in unsigned long position, in unsigned long totalsize); methods oncheckcomplete() called when the update check is completed. void oncheckcomplete( in nsixmlhttprequest request, [array, size_is(updatecount)] in nsiupdate updates, in unsigned long updatecount ); parameters request the nsix...
...mplete() called when the update check is completed. void oncheckcomplete( in nsixmlhttprequest request, [array, size_is(updatecount)] in nsiupdate updates, in unsigned long updatecount ); parameters request the nsixmlhttprequest object handling the update check. updates an array of nsiupdate objects describing the available updates. updatecount the number of updates in the updates array. onerror() called when an error occurs while loading the remote update service file. void onerror( in nsixmlhttprequest request, in nsiupdate update ); parameters request the nsixmlhttprequest object handling the update check. update an nsiupdate object containing details about the error in its statustext attribute. onprogress() called every time there is a progress notification loading the update ...

nsIWifiListener
e is implemented by clients interested in receiving notifications when the list of available wifi access points changes. ...
...ng alen); void onerror(in long error); methods onchange() called when the list of available access points changes. void onchange( [array, size_is(alen)] in nsiwifiaccesspoint accesspoints, in unsigned long alen ); parameters accesspoints an array of nsiwifiaccesspoint objects representing all currently-available wifi access points. alen the number of entries in the accesspoints array. onerror() called when an error occurs while updating the wifi access point list. void onerror( in long error ); parameters error the nsresult value indicating the error that occurred. see also monitoring wifi access points nsiwifimonitor nsiwifiaccesspoint ...

nsIXMLHttpRequest
rface, as seen below in example 2, we can get access to this. the most obvious benefit is that we can set nsirequest - constants in the xhr.channel.loadflags. for instance, as done in example 2, the flag of load_anonymous is added, this strips all user data (cookies, tokens, etc). using event handlers from native code (not sure if it's up-to-date) from native code, the way to set up onload and onerror handlers is a bit different. here is a comment from johnny stenback <jst@netscape.com>: the mozilla implementation of nsixmlhttprequest implements the interface nsidomeventtarget and that's how you're supported to add event listeners. try something like this: nscomptr<nsidomeventtarget> target(do_queryinterface(myxmlhttpreq)); target->addeventlistener(ns_literal_string("load"), mylistener, pr_fa...
...f nsixmlhttprequest implements the interface nsidomeventtarget and that's how you're supported to add event listeners. try something like this: nscomptr<nsidomeventtarget> target(do_queryinterface(myxmlhttpreq)); target->addeventlistener(ns_literal_string("load"), mylistener, pr_false) where mylistener is your event listener object that implements the interface nsidomeventlistener. the 'onload', 'onerror', and 'onreadystatechange' attributes moved to nsijsxmlhttprequest, but if you're coding in c++ you should avoid using those. though actually, if you use addeventlistener from c++ weird things will happen too, since the result will depend on what js happens to be on the stack when you do it.... conclusion: do not use event listeners on xmlhttprequest from c++, unless you're aware of all the sec...

FileReader - Web APIs
has been completed. filereader.result read only the file's contents. this property is only valid after the read operation is complete, and the format of the data depends on which of the methods was used to initiate the read operation. event handlers filereader.onabort a handler for the abort event. this event is triggered each time the reading operation is aborted. filereader.onerror a handler for the error event. this event is triggered each time the reading operation encounter an error. filereader.onload a handler for the load event. this event is triggered each time the reading operation is successfully completed. filereader.onloadstart a handler for the loadstart event. this event is triggered each time the reading is starting. filereader.onloadend a handler for th...
...ional encoding name can be specified. events listen to these events using addeventlistener() or by assigning an event listener to the oneventname property of this interface. abort fired when a read has been aborted, for example because the program called filereader.abort(). also available via the onabort property. error fired when the read failed due to an error. also available via the onerror property. load fired when a read has completed successfully. also available via the onload property. loadend fired when a read has completed, successfully or not. also available via the onloadend property. loadstart fired when a read has started. also available via the onloadstart property. progress fired periodically as data is read. also available via the onprogress property. spec...

Geolocation API - Web APIs
rning the updated location. in both cases, the method call takes up to three arguments: a mandatory success callback: if the location retrieval is successful, the callback executes with a geolocationposition object as its only parameter, providing access to the location data. an optional error callback: if the location retrieval is unsuccessful, the callback executes with a geolocationpositionerror object as its only parameter, providing access information on what went wrong. an optional positionoptions object, which provides options for retrieval of the position data. for further information on geolocation usage, read using the geolocation api. interfaces geolocation the main class of this api — contains methods to retrieve the user's current position, watch for changes in their ...
...nposition instance is returned by a successful call to one of the methods contained inside geolocation, inside a success callback, and contains a timestamp plus a geolocationcoordinates object instance. geolocationcoordinates represents the coordinates of a user's position; a geolocationcoordinates instance contains latitude, longitude, and other important related information. geolocationpositionerror a geolocationpositionerror is returned by an unsuccessful call to one of the methods contained inside geolocation, inside an error callback, and contains an error code and message. navigator.geolocation the entry point into the api. returns a geolocation object instance, from which all other functionality can be accessed. dictionaries positionoptions represents an object containing optio...

HTMLBodyElement - Web APIs
s not handled. windoweventhandlers.onunload is an eventhandler representing the code to be called when the unload event is raised. specifications specification status comment html living standardthe definition of 'htmlbodyelement' in that specification. living standard technically, the event-related properties onafterprint, onbeforeprint, onbeforeunload, onblur, onerror, onfocus, onhashchange, onlanguagechange, onload, onmessage, onoffline, ononline, onpopstate, onresize, onstorage, and onunload, have been moved to windoweventhandlers. htmlbodyelement implements this interface. html 5.1the definition of 'htmlbodyelement' in that specification. recommendation html5the definition of 'htmlbodyelement' in that specification. recommendatio...
...his interface. html 5.1the definition of 'htmlbodyelement' in that specification. recommendation html5the definition of 'htmlbodyelement' in that specification. recommendation the following properties are now obsolete: alink, bgcolor, background, link, text, and vlink. the following properties have been added: onafterprint, onbeforeprint, onbeforeunload, onblur, onerror, onfocus, onhashchange, onload, onmessage, onoffline, ononline, onpopstate, onresize, onstorage, and onunload. document object model (dom) level 2 html specificationthe definition of 'htmlbodyelement' in that specification. obsolete no change from document object model (dom) level 1 specification. document object model (dom) level 1 specificationthe definition of 'htmlbody...

HTMLScriptElement - Web APIs
script> that hosts the following code (through document.currentscript). these scripts will be asynchronously executed. for more details, see the defer and async properties. function loaderror(oerror) { throw new urierror("the script " + oerror.target.src + " didn't load correctly."); } function prefixscript(url, onloadfunction) { var newscript = document.createelement("script"); newscript.onerror = loaderror; if (onloadfunction) { newscript.onload = onloadfunction; } document.currentscript.parentnode.insertbefore(newscript, document.currentscript); newscript.src = url; } this next function, instead of prepending the new scripts immediately before the document.currentscript element, appends them as children of the <head> tag. function loaderror(oerror) { throw new urierror("the s...
... = url; } this next function, instead of prepending the new scripts immediately before the document.currentscript element, appends them as children of the <head> tag. ...

IDBDatabase.onabort - Web APIs
the onabort event handler of the idbdatabase interface handles the abort event, fired when a transaction is aborted and bubbles up to the connection object. note: this feature is available in web workers. syntax idbdatabase.onabort = function(event) { ... ...
...to the connection object. note: this feature is available in web workers. syntax idbdatabase.onabort = function(event) { ... }; example this example shows an idbopendbrequest.onupgradeneeded block that creates a new object store; it also includes onerror and onabort functions to handle non-success cases. ...

IDBDatabase.onversionchange - Web APIs
abase) was requested elsewhere (most probably in another window/tab on the same computer). this is different from the versionchange transaction (but it is related). note: this feature is available in web workers. syntax idbdatabase.onversionchange = function(event) { ... ...
...abase.onversionchange = function(event) { ... } example this example shows an idbopendbrequest.onupgradeneeded block that creates a new object store; it also includes onerror and onabort functions to handle non-success cases, and an onversionchange function to notify when a database structure change has occurred. ...

IDBObjectStore.createIndex() - Web APIs
g used to update the database structure if a database with a higher version number is loaded. createindex() is used to create new indexes on the object store. for a full working example, see our to-do notifications app (view example live.) var db; // let us open our database var dbopenrequest = window.indexeddb.open("todolist", 4); // two event handlers for opening the database. dbopenrequest.onerror = function(event) { note.innerhtml += '<li>error loading database.</li>'; }; dbopenrequest.onsuccess = function(event) { note.innerhtml += '<li>database initialised.</li>'; // store the result of opening the database in the db variable. // this is used a lot below. db = request.result; // run the displaydata() function to populate the task list with // all the to-do list data alr...
...with // all the to-do list data already in the idb displaydata(); }; // this handler fires when a new database is created and indicates // either that one has not been created before, or a new version // was submitted with window.indexeddb.open(). (see above.) // it is only implemented in recent browsers. ...

IDBObjectStore.deleteIndex() - Web APIs
eindex is used to create new indexes on the object store, after which we delete the unneeded old indexes with deleteindex(). for a full working example, see our to-do notifications app (view example live.) var db; // let us open our database var dbopenrequest = window.indexeddb.open("todolist", 4); // these two event handlers act on the database being opened successfully, or not dbopenrequest.onerror = function(event) { note.innerhtml += '<li>error loading database.</li>'; }; dbopenrequest.onsuccess = function(event) { note.innerhtml += '<li>database initialised.</li>'; // store the result of opening the database in the db variable. this is used a lot below db = this.result; // run the displaydata() function to populate the task list with all the to-do list data already in the id...
...to-do list data already in the idb displaydata(); }; // this event handles the event whereby a new version of the database needs to be created // either one has not been created before, or a new version number has been submitted via the // window.indexeddb.open line above //it is only implemented in recent browsers dbopenrequest.onupgradeneeded = function(event) { var db = this.result; db.onerror = function(event) { note.innerhtml += '<li>error loading database.</li>'; }; // create an objectstore for this database var objectstore = db.createobjectstore("todolist", { keypath: "tasktitle" }); // define what data items the objectstore will contain objectstore.createindex("hours", "hours", { unique: false }); objectstore.createindex("minutes", "minutes", { unique: false...

IDBObjectStore - Web APIs
; // store the result of opening the database in db. ...
...duplicate items not allowed.</li>'; }; // create an object store on the transaction var objectstore = transaction.objectstore("todolist"); // make a request to add our newitem object to the object store var objectstorerequest = objectstore.add(newitem[0]); objectstorerequest.onsuccess = function(event) { note.in...

IDBOpenDBRequest: blocked event - Web APIs
a versionchange transaction on the same database. ...
...ion const req2 = indexeddb.open('todolist', 5); // in this case the onblocked handler will be executed req2.addeventlistener('blocked', () => { console.log('request was blocked'); }); }; using the onblocked property: // open the database const dbopenrequest = window.indexeddb.open('todolist', 4); dbopenrequest.onupgradeneeded = (event) => { const db = event.target.result; db.onerror = () => { console.log('error creating database'); }; // create an objectstore for this database var objectstore = db.createobjectstore('todolist', { keypath: 'tasktitle' }); // define what data items the objectstore will contain objectstore.createindex('hours', 'hours', { unique: false }); objectstore.createindex('minutes', 'minutes', { unique: false }); objectstore.createinde...

IDBOpenDBRequest.onblocked - Web APIs
atabase is still in use (that is, not closed) somewhere, even after the versionchange event was sent. note: this feature is available in web workers. syntax idbopendbrequest.onblocked = function(event) { ... }; example var db; // let us open our database var request = indexeddb.open("todolist", 4); // these two event handlers act on the database being opened // successfully, or not request.onerror = function(event) { note.innerhtml += '<li>error loading database.</li>'; }; request.onsuccess = function(event) { note.innerhtml += '<li>database initialised.</li>'; // store the result of opening the database in the db variable. // this is used a lot below db = request.result; // run the displaydata() function to populate the task list with // all the to-do list data already in...
...list data already in the idb displaydata(); }; // this event handles the event whereby a new version of the // database needs to be created. either one has not been created // before, or a new version number has been submitted via the // window.indexeddb.open line above //it is only implemented in recent browsers request.onupgradeneeded = function(event) { var db = event.target.result; db.onerror = function(event) { note.innerhtml += '<li>error loading database.</li>'; }; // create an objectstore for this database var objectstore = db.createobjectstore("todolist", { keypath: "tasktitle" }); ... }; request.onblocked = function() { console.log("your database version can't be upgraded because the app is open somewhere else."); } specifications specification sta...

IDBOpenDBRequest.onupgradeneeded - Web APIs
) var db; // request version 3 of the database. var request = window.indexeddb.open("library", 3); // this event handles the event whereby a new version of the // database needs to be created. either one has not been created // before, or a new version number has been submitted via the // window.indexeddb.open line above. request.onupgradeneeded = function(event) { db = request.result; db.onerror = function(errorevent) { note.innerhtml += '<li>error loading database.</li>'; }; if (event.oldversion < 1) { // version 1 is the first version of the database. var store = db.createobjectstore("books", {keypath: "isbn"}); var titleindex = store.createindex("by_title", "title", {unique: true}); var authorindex = store.createindex("by_author", "author"); } if (event.ol...
... var yearindex = bookstore.createindex("by_year", "year"); } if (event.oldversion < 3) { // version 3 introduces a new object store for magazines with two indexes. var magazines = db.createobjectstore("magazines"); var publisherindex = magazines.createindex("by_publisher", "publisher"); var frequencyindex = magazines.createindex("by_frequency", "frequency"); } }; request.onerror = function(event) { note.innerhtml += '<li>error loading database.</li>'; }; request.onsuccess = function(event) { note.innerhtml += '<li>database initialised.</li>'; db = request.result; populateanddisplaydata(); }; specifications specification status comment indexed database api 2.0the definition of 'onupgradeneeded' in that specification. recommendation ...

IDBOpenDBRequest - Web APIs
ing example you can see the onupgradeneeded handler being used to update the database structure if a database with a higher version number is loaded. for a full working example, see our to-do notifications app (view example live.) var db; // let us open our database var dbopenrequest = window.indexeddb.open("todolist", 4); // these event handlers act on the database being opened. dbopenrequest.onerror = function(event) { note.innerhtml += '<li>error loading database.</li>'; }; dbopenrequest.onsuccess = function(event) { note.innerhtml += '<li>database initialised.</li>'; // store the result of opening the database in the db // variable. this is used a lot below db = dbopenrequest.result; // run the displaydata() function to populate the task // listwith all the to-do list data...
...o list data already in the idb displaydata(); }; // this event handles the event whereby a new version of // the database needs to be created either one has not // been created before, or a new version number has been // submitted via the window.indexeddb.open line above // it is only implemented in recent browsers dbopenrequest.onupgradeneeded = function(event) { var db = this.result; db.onerror = function(event) { note.innerhtml += '<li>error loading database.</li>'; }; // create an objectstore for this database var objectstore = db.createobjectstore("todolist", { keypath: "tasktitle" }); // define what data items the objectstore will contain objectstore.createindex("hours", "hours", { unique: false }); objectstore.createindex("minutes", "minutes", { unique: false...

IDBRequest: success event - Web APIs
bubbles no cancelable no interface event event handler property onsuccess examples this example tries to open a database and listens for the success event using addeventlistener(): // open the database const openrequest = window.indexeddb.open('todolist', 4); openrequest.onupgradeneeded = (event) => { const db = event.target.result; db.onerror = () => { console.log('error creating database'); }; // create an objectstore for this database var objectstore = db.createobjectstore('todolist', { keypath: 'tasktitle' }); // define what data items the objectstore will contain objectstore.createindex('hours', 'hours', { unique: false }); objectstore.createindex('minutes', 'minutes', { unique: false }); objectstore.createinde...
...jectstore.createindex('year', 'year', { unique: false }); }; openrequest.addeventlistener('success', (event) => { console.log('database opened successfully!'); }); the same example, but using the onsuccess event handler property: // open the database const openrequest = window.indexeddb.open('todolist', 4); openrequest.onupgradeneeded = (event) => { const db = event.target.result; db.onerror = () => { console.log('error creating database'); }; // create an objectstore for this database var objectstore = db.createobjectstore('todolist', { keypath: 'tasktitle' }); // define what data items the objectstore will contain objectstore.createindex('hours', 'hours', { unique: false }); objectstore.createindex('minutes', 'minutes', { unique: false }); objectstore.createinde...

IDBTransaction: abort event - Web APIs
ardware failure) quota exceeded. examples this example opens a database (creating the database if it does not exist), then opens a transaction, adds a listener to the abort event, then aborts the transaction to trigger the event. ...
...ort` transaction.addeventlistener('abort', () => { console.log('transaction was aborted'); }); // abort the transaction transaction.abort(); }; the same example, but assigning the event handler to the onabort property: // open the database const dbopenrequest = window.indexeddb.open('todolist', 4); dbopenrequest.onupgradeneeded = event => { const db = event.target.result; db.onerror = () => { console.log('error creating database'); }; // create an objectstore for this database var objectstore = db.createobjectstore('todolist', { keypath: 'tasktitle' }); // define what data items the objectstore will contain objectstore.createindex('hours', 'hours', { unique: false }); objectstore.createindex('minutes', 'minutes', { unique: false }); objectstore.createinde...

IDBTransaction: complete event - Web APIs
ete handler is executed when a transaction successfully completed. ...
...ansaction.objectstore('todolist'); const newitem = { tasktitle: 'my task', hours: 10, minutes: 10, day: 10, month: 'january', year: 2019 }; const objectstorerequest = objectstore.add(newitem); }; using the oncomplete property: // open the database const dbopenrequest = window.indexeddb.open('todolist', 4); dbopenrequest.onupgradeneeded = event => { const db = event.target.result; db.onerror = () => { console.log('error creating database'); }; // create an objectstore for this database var objectstore = db.createobjectstore('todolist', { keypath: 'tasktitle' }); // define what data items the objectstore will contain objectstore.createindex('hours', 'hours', { unique: false }); objectstore.createindex('minutes', 'minutes', { unique: false }); objectstore.createinde...

IDBTransaction.error - Web APIs
ished, is finished and successfully committed, or was aborted with the idbtransaction.abort method. example in the following code snippet, we open a read/write transaction on our database and add some data to an object store. note also the functions attached to transaction event handlers to report on the outcome of the transaction opening in the event of success or failure. note the transaction.onerror = function(event) { }; block, making use of transaction.error to help in reporting what went wrong when the transaction was unsuccessful. for a full working example, see our to-do notifications app (view example live.) // let us open our database var dbopenrequest = window.indexeddb.open("todolist", 4); dbopenrequest.onsuccess = function(event) { note.innerhtml += '<li>database initialised.</...
... day: 24, month: "december", year: 2013, notified: "no" } ]; // open a read/write db transaction, ready for adding the data var transaction = db.transaction(["todolist"], "readwrite"); // report on the success of opening the transaction transaction.oncomplete = function(event) { note.innerhtml += '<li>transaction completed: database modification finished.</li>'; }; transaction.onerror = function(event) { note.innerhtml += '<li>transaction not opened due to error: ' + transaction.error + '</li>'; }; // create an object store on the transaction var objectstore = transaction.objectstore("todolist"); // add our newitem object to the object store var objectstorerequest = objectstore.add(newitem[0]); objectstorerequest.onsuccess = function(event) { // report t...

MediaRecorder: error event - Web APIs
the mediarecorder interface's error event is fired when an error occurs: for example because recording wasn't allowed or was attempted using an unsupported codec. bubbles no cancelable no interface mediarecordererrorevent event handler property onerror for details of the all the possible errors see the documentation for the event handler property: onerror. examples using addeventlistener to listen for error events: async function record() { const stream = await navigator.mediadevices.getusermedia({audio: true}); const recorder = new mediarecorder(stream); recorder.addeventlistener('error', (event) => { console.error(`error recording stream: ${event.error.name}`) }); recorder.start(); } record(); the same, bu...
...amples using addeventlistener to listen for error events: async function record() { const stream = await navigator.mediadevices.getusermedia({audio: true}); const recorder = new mediarecorder(stream); recorder.addeventlistener('error', (event) => { console.error(`error recording stream: ${event.error.name}`) }); recorder.start(); } record(); the same, but using the onerror event handler property: async function record() { const stream = await navigator.mediadevices.getusermedia({audio: true}); const recorder = new mediarecorder(stream); recorder.onerror = (event) => { console.error(`error recording stream: ${event.error.name}`) }; recorder.start(); } record(); specifications specification status mediastream recor...

MediaRecorder - Web APIs
ilable called to handle the dataavailable event, which is periodically triggered each time timeslice milliseconds of media have been recorded (or when the entire media has been recorded, if timeslice wasn't specified). the event, of type blobevent, contains the recorded media in its data property. you can then collect and act upon that recorded media data using this event handler. mediarecorder.onerror an eventhandler called to handle the error event, including reporting errors that arise with media recording. these are fatal errors that stop recording. the received event is based on the mediarecordererrorevent interface, whose error property contains a domexception that describes the actual error that occurred. mediarecorder.onpause an eventhandler called to handle the pause event, which oc...
...dia recording ends, either when the mediastream ends — or after the mediarecorder.stop() method is called. events listen to these events using addeventlistener() or by assigning an event listener to the oneventname property of this interface. error fired when an error occurs: for example because recording wasn't allowed or was attempted using an unsupported codec. also available via the onerror property. example if (navigator.mediadevices) { console.log('getusermedia supported.'); var constraints = { audio: true }; var chunks = []; navigator.mediadevices.getusermedia(constraints) .then(function(stream) { var mediarecorder = new mediarecorder(stream); visualize(stream); record.onclick = function() { mediarecorder.start(); console.log(mediarecorde...

MediaRecorderErrorEvent.error - Web APIs
ead-only error property in the mediarecordererrorevent interface is a domexception object providing details about the exception that was thrown by a mediarecorder instance. when a media​recorder​error​event occurs, you can determine to some extent what went wrong by examining the error property within the media​recorder​error​event received by the mediarecorder's error event handler, onerror. syntax error = mediarecordererrorevent.error; value a domexception describing the error represented by the event. the error's name property's value may be any exception that makes sense during the handling of media recording, including these specifically identified by the specification. the descriptions here are generic ones; you'll find more specific ones to various scenarios in which they...
...ven mediastream, configured to buffer data into an array and to watch for errors. function recordstream(stream) { let recorder = null; let bufferlist = []; try { recorder = new mediarecorder(stream); } catch(err) { /* exception while trying to create the recorder; handle that */ } recorder.ondataavailable = function(event) { bufferlist.push(event.data); }; recorder.onerror = function(event) { let error = event.error; }; recorder.start(100); /* 100ms time slices per buffer */ return recorder; } specifications specification status comment mediastream recordingthe definition of 'mediarecordererrorevent.error' in that specification. working draft initial specification. ...

Recording a media element - Web APIs
we always record no more than the specified nu...
...he event handler simply pushes the blob onto the data array. lines 6-7 starts the recording process by calling recorder.start(), and outputs a message to the log with the updated state of the recorder and the number of seconds it will be recording. lines 9-12 creates a new promise, named stopped, which is resolved when the mediarecorder's onstop event handler is called, and is rejected if its onerror event handler is called. the rejection handler receives as input the name of the error that occurred. lines 14-16 creates a new promise, named recorded, which is resolved when the specified number of milliseconds have elapsed. upon resolution, it stops the mediarecorder if it's recording. lines 18-22 these lines create a new promise which is fulfilled when both of the two promises (stopped an...

RTCDataChannel: error event - Web APIs
a webrtc error event is sent to an rtcdatachannel object's onerror error handler when an error occurs on the data channel. bubbles yes cancelable no interface rtcerrorevent event handler property onerror the rtcerrorevent object provides details about the error that occurred; see that article for details. examples // strings for each of the sctp cause codes found in rfc // 4960, section 3.3.10: // https://tools.ietf.org/html/rfc4960#section-3.3.10 const sctpcausecodes = [ "no sctp error", "invalid stream identifier", "missing mandatory parameter", "stale cookie error", "sender is out of resource (i.e., memory)", "unable to resolve address", "unrecognized sctp chunk type received", "invalid mandatory parameter", "unrecog...
...information may be output. each error type has a different set of information output. for example, an sdp syntax error displays the line number of the error within the sdp, and an sctp error displays a message corresponding to the sctp cause code. other error types similarly output appropriate information. you can also set up an event handler for error events using the rtcdatachannel interface's onerror event handler property: dc.onerror = ev => { const err = ev.error; /* ... */ } note: since rtcerror is not one of the legacy errors, the value of rtcerror.code is always 0. specifications specification status comment webrtc 1.0: real-time communication between browsersthe definition of 'error event' in that specification. candidate recommendation initi...

RTCDataChannel - Web APIs
losing property is an eventhandler which specifies a function to be called by the browser when the closing event is received by the rtcdatachannel. this is a simple event which indicates that the data channel is being closed, that is, rtcdatachannel transitions to "closing" state. for example, after rtcdatachannel.close() was called but the underlying data transport might not have been closed yet.onerror the rtcdatachannel.onerror property is an eventhandler which specifies a function to be called when the error event is received. when an error occurs on the data channel, the function receives as input an errorevent object describing the error which occurred.onmessage the rtcdatachannel.onmessage property stores an eventhandler which specifies a function to be called when the message event is f...
... the rtcdatachannel interface sends data across the data channel to the remote peer. events bufferedamountlow sent to the channel's onbufferedamountlow event handler when the number of bytes of data in the outgoing data buffer falls below the value specified by bufferedamountlowthreshold. close sent to the onclose event handler when the underlying data transport closes. error sent to the onerror event handler when an error occurs on the data channel. message sent to the onmessage event handler when a message has been received from the remote peer. the message contents can be found in the event's data property. open sent to the onopen event handler when the data channel is first opened, or when an existing data channel's underlying connection re-opens. data format the underlying da...

RTCError - Web APIs
erty is a long integer identifying the line number of the sdp on which the syntax error occurred. null if the error isn't an sdp syntax error. sentalert read only if errordetail is dtls-failure, this property is an unsigned long integer indicating the fatal dtls error that was sent out by this device. if null, no dtls error was transmitted. all rtcerror objects have their name set to operationerror. examples in this example, a handler is established for an rtcdatachannel's error event. datachannel.addeventlistener("error", (event) => { let error = event.error; if (error.errordetail === "sdp-syntax-error") { let errline = error.sdplinenumber; let errmessage = error.message; let alertmessage = `a syntax error occurred interpreting line ${errline} of the sdp: ${errmessag...
...sdp at which the error occurred. this message is then displayed using a function called showmyalertmessage(), which stands in for whatever output mechanism this code might use. any other error is treated as terminal, causing a terminatemyconnection() function to be called. the above example uses addeventlistener() to add the handler for error events. you can also use the rtcdatachannel object's onerror event handler property, like this: datachannel.onerror = (event) => { let error = event.error; /* and so forth */ }; specifications specification status comment webrtc 1.0: real-time communication between browsersthe definition of 'rtcerror' in that specification. candidate recommendation initial definition. ...

RTCErrorEvent.error - Web APIs
erty is a long integer identifying the line number of the sdp on which the syntax error occurred. null if the error isn't an sdp syntax error. sentalert read only if errordetail is dtls-failure, this property is an unsigned long integer indicating the fatal dtls error that was sent out by this device. if null, no dtls error was transmitted. all rtcerror objects have their name set to operationerror. examples in this example, a handler is established for an rtcdatachannel's error event. datachannel.addeventlistener("error", (event) => { let error = event.error; if (error.errordetail === "sdp-syntax-error") { let errline = error.sdplinenumber; let errmessage = error.message; let alertmessage = `a syntax error occurred interpreting line ${errline} of the sdp: ${errmessage...
...sdp at which the error occurred. this message is then displayed using a function called showmyalertmessage(), which stands in for whatever output mechanism this code might use. any other error is treated as terminal, causing a terminatemyconnection() function to be called. the above example uses addeventlistener() to add the handler for error events. you can also use the rtcdatachannel object's onerror event handler property, like this: datachannel.onerror = (event) => { let error = event.error; /* and so forth */ }; specifications specification status comment webrtc 1.0: real-time communication between browsersthe definition of 'rtcerrorevent.error' in that specification. candidate recommendation initial definition. ...

RTCIdentityErrorEvent - Web APIs
firefox implements this interface under the following name: rtcpeerconnectionidentityerrorevent. it is likely that it will correct this name when it will unprefix rtcpeerconnection, once spec and implementation will have been stabilized. properties a rtcidentityerrorevent being an event, this event also implements these properties. ...
...ring giving the url where the user can complete the authentication. it can be null and is provided by the identity provider (idp). rtcidentityerrorevent.protocol read only is a domstring describing the idp protocol in use. ...

RTCPeerConnection.createAnswer() - Web APIs
iscouraged. you should update any existing code to use the promise-based version of createanswer() instead. the parameters for this form of createanswer() are described below, to aid in updating existing code. successcallback an rtcsessiondescriptioncallback which will be passed a single rtcsessiondescription object describing the newly-created answer. ...
... return value a promise whose fulfillment handler is called with an object conforming to the rtcsessiondescriptioninit dictionary which contains the sdp answer to be delivered to the other peer. ...

RTCPeerConnection.createOffer() - Web APIs
gly discouraged. you should update any existing code to use the promise-based version of createoffer() instead. the parameters for this form of createoffer() are described below, to aid in updating existing code. successcallback an rtcsessiondescriptioncallback which will be passed a single rtcsessiondescription object describing the newly-created offer. errorcallback an rtcpeerconnectionerrorcallback which will be passed a single domexception object explaining why the request to create an offer failed. options optional an optional rtcofferoptions dictionary providing options requested for the offer. return value a promise whose fulfillment handler will receive an object conforming to the rtcsessiondescriptioninit dictionary which contains the sdp describing the generated offer. t...
...urned promise. your rejection handler should examine the received exception to determine which occurred. invalidstateerror the rtcpeerconnection is closed. notreadableerror no certificate or set of certificates was provided for securing the connection, and createoffer() was unable to create a new one. since all webrtc connections are required to be secured, that results in an error. operationerror examining the state of the system to determine resource availability in order to generate the offer failed for some reason. example here we see a handler for the negotiationneeded event which creates the offer and sends it to the remote system over a signaling channel. note: keep in mind that this is part of the signaling process, the transport layer for which is an implementation detail th...

RTCPeerConnection.setLocalDescription() - Web APIs
e parameters for the older form of setlocaldescription() are described below, to aid in updating existing code. successcallback a javascript function which accepts no input parameters to be be called once the description has been successfully set. at that time, the offer can be sent to a remote peer via the signaling server. errorcallback a function matching the signature rtcpeerconnectionerrorcallback which gets called if the description can't be set. it is passed a single domexception object explaining why the request failed. this deprecated form of the method returns instantaneously without waiting for the actual setting to be done: in case of success, the successcallback will be called; in case of failure, the errorcallback will be called. deprecated exceptions when using the de...
...ccesscallback will be called; in case of failure, the errorcallback will be called. deprecated exceptions when using the deprecated callback-based version of setlocaldescription(), the following exceptions may occur: invalidstateerror the connection's signalingstate is "closed", indicating that the connection is not currently open, so negotiation cannot take place. invalidsessiondescriptionerror the rtcsessiondescription specified by the sessiondescription parameter is invalid. examples implicit descriptions one of the advantages of the parameter-free form of setlocaldescription() is that it lets you simplify your negotiation code substantially. this is all your negotiationneeded event handler needs to look like, for the most part. just add the signaling server code, which here is...

RTCRtpSender.setParameters() - Web APIs
ied; this value is used to ensure that setparameters() can only be called to alter changes made by a specific previous call to getparameters(). return value a promise that resolves when the rtcrtpsender.track property is updated with the given parameters. exceptions if an error occurs, the returned promise is rejected with the appropriate exception from the list below. invalidmodificationerror one of the following problems was detected: the number of encodings specified in the parameters object's encodings property does not match the number of encodings currently listed for the rtcrtpsender. you cannot change the number of encoding options once the sender has been created. the order of the specified encodings has changed from the current list's order. an attempt has been made ...
... you cannot change the number of encoding options once the sender has been created. the order of the specified encodings has changed from the current list's order. an attempt has been made to alter a property that cannot be changed after the sender is first created. invalidstateerror the transceiver of which the rtcrtpsender is a part is not running, or has no parameters to set. operationerror any error condition which occurs that isn't covered by one of the other error codes results in an operationerror. rangeerror the value specified for scaleresolutiondownby is less than 1.0, which would result in scaling up rather than down, which is not allowed; or one or more of the specified encodings' maxframerate values is less than 0.0. in addition, if a webrtc error occurs while configu...

Sensor APIs - Web APIs
ming requires three strategies. checking for thrown errors when instantiating a sensor object. listening for errors thrown during its use. handling the errors gracefully so that the user experience is enhanced rather than degraded. the code example below illustrates these principles. the try...catch block catches errors thrown during sensor instantiation. it implements a handler for sensor.onerror to catch errors thrown during use. the only time anything is shown to the user is when permissions need to be requested and when the sensor type isn't supported by the device. if a feature policy blocks use of a feature it is because your code is inconsistent with the policies set on your server. this is not something that would ever be shown to a user. see feature-policy for implementation ins...
...o use the sensor. navigator.permissions.query({ name: 'accelerometer' }) .then(result => { if (result.state === 'denied') { console.log('permission to use accelerometer sensor is denied.'); return; } // use the sensor. }); an alternative approach is to attempt to use the error and listen for the securityerror. const sensor = new absoluteorientationsensor(); sensor.start(); sensor.onerror = event => { if (event.error.name === 'securityerror') console.log("no permissions to use absoluteorientationsensor."); }; the following table describes for each sensor type, the name required for the permissions api, the <iframe> element's allow attribute and the feature-policy directive. sensor permissions sensor permission/feature policy name absoluteorientati...

SpeechSynthesisUtterance: error event - Web APIs
the error event of the web speech api speechsynthesisutterance object is fired when an error occurs that prevents the utterance from being succesfully spoken. ...
...m being succesfully spoken. bubbles no cancelable no interface speechsynthesiserrorevent event handler property onerror examples you can use the error event in an addeventlistener method: utterthis.addeventlistener('error', function(event) { console.log('an error has occurred with the speech synthesis: ' + event.error'); }); or use the onerror event handler property: utterthis.onerror = function(event) { console.log('an error has occurred with the speech synthesis: ' + event.error'); } specifications specification status comment web speech apithe definition of 'speech synthesis utterance events' in that specification. draft ...

WebSocket - Web APIs
pen 1 websocket.closing 2 websocket.closed 3 properties websocket.binarytype the binary data type used by the connection. websocket.bufferedamount read only the number of bytes of queued data. websocket.extensions read only the extensions selected by the server. websocket.onclose an event listener to be called when the connection is closed. websocket.onerror an event listener to be called when an error occurs. websocket.onmessage an event listener to be called when a message is received from the server. websocket.onopen an event listener to be called when the connection is opened. websocket.protocol read only the sub-protocol selected by the server. websocket.readystate read only the current state of the connection. websocket.url read onl...
...itted. events listen to these events using addeventlistener() or by assigning an event listener to the oneventname property of this interface. close fired when a connection with a websocket is closed. also available via the onclose property error fired when a connection with a websocket has been closed because of an error, such as when some data couldn't be sent. also available via the onerror property. message fired when data is received through a websocket. also available via the onmessage property. open fired when a connection with a websocket is opened. also available via the onopen property. examples // create websocket connection. const socket = new websocket('ws://localhost:8080'); // connection opened socket.addeventlistener('open', function (event) { socket.send(...

Window - Web APIs
event handler property for change events on the window. globaleventhandlers.onclick called after the any mouse button is pressed & released globaleventhandlers.ondblclick called when a double click is made with any mouse button. globaleventhandlers.onclose called after the window is closed globaleventhandlers.oncontextmenu called when the right mouse button is pressed globaleventhandlers.onerror called when a resource fails to load or when an error occurs at runtime. see error event. globaleventhandlers.onfocus called after the window receives or regains focus. see focus events. windoweventhandlers.onhashchange an event handler property for hashchange events on the window; called when the part of the url after the hash mark ("#") changes. globaleventhandlers.oninput called when th...
...windoweventhandlers.onunload called when the user navigates away from the page. events listen to these events using addeventlistener() or by assigning an event listener to the oneventname property of this interface. error fired when a resource failed to load, or can't be used. for example, if a script has an execution error or an image can't be found or is invalid. also available via the onerror property. languagechange fired at the global scope object when the user's preferred language changes. also available via the onlanguagechange property. orientationchange fired when the orientation of the device has changed. also available via the onorientationchange property. devicemotion fired at a regular interval, indicating the amount of physical force of acceleration the device is re...

XDomainRequest - Web APIs
specifing the method (get/post) and url. xdomainrequest.send() sends the request. post data is specified in this method. xdomainrequest.abort() aborts the request. event handlers xdomainrequest.onprogress a handler for when the request has made progress between the send method call and the onload event. xdomainrequest.ontimeout a handler for when the request times out. ...
...xdomainrequest.onerror a handler for when a request has errored. xdomainrequest.onload a handler for when the full response has been received from the server. example if(window.xdomainrequest){ var xdr = new xdomainrequest(); xdr.open("get", "http://example.com/api/method"); xdr.onprogress = function () { //progress }; xdr.ontimeout = function () { //timeout }; xdr.onerror = function () { //error occurred }; xdr.onload = function() { //success(xdr.responsetext); } settimeout(function () { xdr.send(); }, 0); } note: the xdr.send() call is wrapped in a timeout (see window.settimeout() to prevent an issue with the interface where some requests are lost if multiple xdomainrequests are being sent at the same time. note: the xdr.onprogress ev...

Synchronous and asynchronous requests - Web APIs
ile your request is being handled. example: send a file to the console log this is the simplest usage of asynchronous xmlhttprequest. var xhr = new xmlhttprequest(); xhr.open("get", "/bar/foo.txt", true); xhr.onload = function (e) { if (xhr.readystate === 4) { if (xhr.status === 200) { console.log(xhr.responsetext); } else { console.error(xhr.statustext); } } }; xhr.onerror = function (e) { console.error(xhr.statustext); }; xhr.send(null); line 2 specifies true for its third parameter to indicate that the request should be handled asynchronously. line 3 creates an event handler function object and assigns it to the request's onload attribute. this handler looks at the request's readystate to see if the transaction is complete in line 4; if it is, and the http s...
...ead file to a specified listener. function xhrsuccess() { this.callback.apply(this, this.arguments); } function xhrerror() { console.error(this.statustext); } function loadfile(url, callback /*, opt_arg1, opt_arg2, ... ...

XMLHttpRequest: abort event - Web APIs
ut class="xhr abort" type="button" name="xhr" value="click to start xhr (abort)" /> </div> <textarea readonly class="event-log"></textarea> css .event-log { width: 25rem; height: 4rem; border: 1px solid black; margin: .5rem; padding: .2rem; } input { width: 11rem; margin: .5rem; } js const xhrbuttonsuccess = document.queryselector('.xhr.success'); const xhrbuttonerror = document.queryselector('.xhr.error'); const xhrbuttonabort = document.queryselector('.xhr.abort'); const log = document.queryselector('.event-log'); function handleevent(e) { log.textcontent = log.textcontent + `${e.type}: ${e.loaded} bytes transferred\n`; } function addlisteners(xhr) { xhr.addeventlistener('loadstart', handleevent); xhr.addeventlistener('load', handleevent); ...
...deventlistener('error', handleevent); xhr.addeventlistener('abort', handleevent); } function runxhr(url) { log.textcontent = ''; const xhr = new xmlhttprequest(); addlisteners(xhr); xhr.open("get", url); xhr.send(); return xhr; } xhrbuttonsuccess.addeventlistener('click', () => { runxhr('https://mdn.mozillademos.org/files/16553/dgszyjnxcaipwzy.jpg'); }); xhrbuttonerror.addeventlistener('click', () => { runxhr('https://somewhere.org/i-dont-exist'); }); xhrbuttonabort.addeventlistener('click', () => { runxhr('https://mdn.mozillademos.org/files/16553/dgszyjnxcaipwzy.jpg').abort(); }); result specifications specification status comment xmlhttprequest living standard ...

XMLHttpRequest: load event - Web APIs
ut class="xhr abort" type="button" name="xhr" value="click to start xhr (abort)" /> </div> <textarea readonly class="event-log"></textarea> css .event-log { width: 25rem; height: 4rem; border: 1px solid black; margin: .5rem; padding: .2rem; } input { width: 11rem; margin: .5rem; } js const xhrbuttonsuccess = document.queryselector('.xhr.success'); const xhrbuttonerror = document.queryselector('.xhr.error'); const xhrbuttonabort = document.queryselector('.xhr.abort'); const log = document.queryselector('.event-log'); function handleevent(e) { log.textcontent = log.textcontent + `${e.type}: ${e.loaded} bytes transferred\n`; } function addlisteners(xhr) { xhr.addeventlistener('loadstart', handleevent); xhr.addeventlistener('load', handleevent); ...
...deventlistener('error', handleevent); xhr.addeventlistener('abort', handleevent); } function runxhr(url) { log.textcontent = ''; const xhr = new xmlhttprequest(); addlisteners(xhr); xhr.open("get", url); xhr.send(); return xhr; } xhrbuttonsuccess.addeventlistener('click', () => { runxhr('https://mdn.mozillademos.org/files/16553/dgszyjnxcaipwzy.jpg'); }); xhrbuttonerror.addeventlistener('click', () => { runxhr('https://somewhere.org/i-dont-exist'); }); xhrbuttonabort.addeventlistener('click', () => { runxhr('https://mdn.mozillademos.org/files/16553/dgszyjnxcaipwzy.jpg').abort(); }); result specifications specification status comment xmlhttprequest living standard ...

XMLHttpRequest: loadend event - Web APIs
ut class="xhr abort" type="button" name="xhr" value="click to start xhr (abort)" /> </div> <textarea readonly class="event-log"></textarea> css .event-log { width: 25rem; height: 4rem; border: 1px solid black; margin: .5rem; padding: .2rem; } input { width: 11rem; margin: .5rem; } js const xhrbuttonsuccess = document.queryselector('.xhr.success'); const xhrbuttonerror = document.queryselector('.xhr.error'); const xhrbuttonabort = document.queryselector('.xhr.abort'); const log = document.queryselector('.event-log'); function handleevent(e) { log.textcontent = log.textcontent + `${e.type}: ${e.loaded} bytes transferred\n`; } function addlisteners(xhr) { xhr.addeventlistener('loadstart', handleevent); xhr.addeventlistener('load', handleevent); ...
...deventlistener('error', handleevent); xhr.addeventlistener('abort', handleevent); } function runxhr(url) { log.textcontent = ''; const xhr = new xmlhttprequest(); addlisteners(xhr); xhr.open("get", url); xhr.send(); return xhr; } xhrbuttonsuccess.addeventlistener('click', () => { runxhr('https://mdn.mozillademos.org/files/16553/dgszyjnxcaipwzy.jpg'); }); xhrbuttonerror.addeventlistener('click', () => { runxhr('https://somewhere.org/i-dont-exist'); }); xhrbuttonabort.addeventlistener('click', () => { runxhr('https://mdn.mozillademos.org/files/16553/dgszyjnxcaipwzy.jpg').abort(); }); result specifications specification status comment xmlhttprequest living standard ...

XMLHttpRequest: loadstart event - Web APIs
ut class="xhr abort" type="button" name="xhr" value="click to start xhr (abort)" /> </div> <textarea readonly class="event-log"></textarea> css .event-log { width: 25rem; height: 4rem; border: 1px solid black; margin: .5rem; padding: .2rem; } input { width: 11rem; margin: .5rem; } js const xhrbuttonsuccess = document.queryselector('.xhr.success'); const xhrbuttonerror = document.queryselector('.xhr.error'); const xhrbuttonabort = document.queryselector('.xhr.abort'); const log = document.queryselector('.event-log'); function handleevent(e) { log.textcontent = log.textcontent + `${e.type}: ${e.loaded} bytes transferred\n`; } function addlisteners(xhr) { xhr.addeventlistener('loadstart', handleevent); xhr.addeventlistener('load', handleevent); ...
...deventlistener('error', handleevent); xhr.addeventlistener('abort', handleevent); } function runxhr(url) { log.textcontent = ''; const xhr = new xmlhttprequest(); addlisteners(xhr); xhr.open("get", url); xhr.send(); return xhr; } xhrbuttonsuccess.addeventlistener('click', () => { runxhr('https://mdn.mozillademos.org/files/16553/dgszyjnxcaipwzy.jpg'); }); xhrbuttonerror.addeventlistener('click', () => { runxhr('https://somewhere.org/i-dont-exist'); }); xhrbuttonabort.addeventlistener('click', () => { runxhr('https://mdn.mozillademos.org/files/16553/dgszyjnxcaipwzy.jpg').abort(); }); result specifications specification status comment xmlhttprequest living standard ...

XMLHttpRequest: progress event - Web APIs
ut class="xhr abort" type="button" name="xhr" value="click to start xhr (abort)" /> </div> <textarea readonly class="event-log"></textarea> css .event-log { width: 25rem; height: 4rem; border: 1px solid black; margin: .5rem; padding: .2rem; } input { width: 11rem; margin: .5rem; } js const xhrbuttonsuccess = document.queryselector('.xhr.success'); const xhrbuttonerror = document.queryselector('.xhr.error'); const xhrbuttonabort = document.queryselector('.xhr.abort'); const log = document.queryselector('.event-log'); function handleevent(e) { log.textcontent = log.textcontent + `${e.type}: ${e.loaded} bytes transferred\n`; } function addlisteners(xhr) { xhr.addeventlistener('loadstart', handleevent); xhr.addeventlistener('load', handleevent); ...
...deventlistener('error', handleevent); xhr.addeventlistener('abort', handleevent); } function runxhr(url) { log.textcontent = ''; const xhr = new xmlhttprequest(); addlisteners(xhr); xhr.open("get", url); xhr.send(); return xhr; } xhrbuttonsuccess.addeventlistener('click', () => { runxhr('https://mdn.mozillademos.org/files/16553/dgszyjnxcaipwzy.jpg'); }); xhrbuttonerror.addeventlistener('click', () => { runxhr('https://somewhere.org/i-dont-exist'); }); xhrbuttonabort.addeventlistener('click', () => { runxhr('https://mdn.mozillademos.org/files/16553/dgszyjnxcaipwzy.jpg').abort(); }); result specifications specification status comment xmlhttprequest living standard ...

XMLHttpRequest - Web APIs
rtobsolete since gecko 22 this gecko-only feature, a boolean, was removed in firefox/gecko 22. please use server-sent events, web sockets, or responsetext from progress events instead. event handlers onreadystatechange as a property of the xmlhttprequest instance is supported in all browsers. since then, a number of additional event handlers have been implemented in various browsers (onload, onerror, onprogress, etc.). see using xmlhttprequest. more recent browsers, including firefox, also support listening to the xmlhttprequest events via standard addeventlistener() apis in addition to setting on* properties to a handler function. methods xmlhttprequest.abort() aborts the request if it has already been sent. xmlhttprequest.getallresponseheaders() returns all the response headers, se...
... javascript code, use open() instead. see the documentation for open(). xmlhttprequest.sendasbinary() a variant of the send() method that sends binary data. events abort fired when a request has been aborted, for example because the program called xmlhttprequest.abort(). also available via the onabort property. error fired when the request encountered an error. also available via the onerror property. load fired when an xmlhttprequest transaction completes successfully. also available via the onload property. loadend fired when a request has completed, whether successfully (after load) or unsuccessfully (after abort or error). also available via the onloadend property. loadstart fired when a request has started to load data. also available via the onloadstart property. prog...

SVG Event Attributes - SVG: Scalable Vector Graphics
upports, svg supports that as an event attribute, following the same requirements as for html event attributes. the global event attributes are available on all svg elements. other event attributes are available on a case by case basis for each elements. all event attribute are not animatable. ...
...in, onend, onrepeat document event attributes onabort, onerror, onresize, onscroll, onunload document element event attributes oncopy, oncut, onpaste global event attributes oncancel, oncanplay, oncanplaythrough, onchange, onclick, onclose, oncuechange, ondblclick, ondrag, ondragend, ondragenter, ondragexit, ondragleave, ondragover, ondragstart, ondrop, ondurationchange, onemptied, onended, onerror, onfocus, oninput, oninvalid, onkeydown, onkeypress, onkeyup, onload, onloadeddata, onloadedmetadata, onloadstart, onmousedown, onmouseenter, onmouseleave, onmousemove, onmouseout, onmouseover, onmouseup, onmousewheel, onpause, onplay, onplaying, onprogress, onratechange, onreset, onresize, onscroll, onseeked, onseeking, onselect, onshow, onstalled, onsubmit, onsuspend, ontimeupdate, ontoggle, on...

tabs - Archive of obsolete content
a: "blah" } }); } }); the values are accessible to content scripts via the self.options property: // content-script.js alert(self.options.a); onmessage function a function called when the content worker receives a message from content scripts. listeners are passed a single argument, the message posted from the content script. optional. onerror function a function called when the content worker receives an error from content scripts. listeners are passed a single argument, error, which is the error posted from the content script and an object of type error. optional returns worker : the worker object can be used to communicate with the content script. see content scripts guide to learn the details. properties id the uni...

content/worker - Archive of obsolete content
loaded before those specified by the contentscript option. optional. contentscript string,array the texts of content scripts to load. content scripts specified by this option are loaded after those specified by the contentscriptfile option. optional. onmessage function functions that will registered as a listener to a 'message' events. onerror function functions that will registered as a listener to an 'error' events. worker worker is composed from the eventemitter trait, therefore instances of worker and their descendants expose all the public properties exposed by eventemitter along with additional public properties that are listed below. methods postmessage(data) asynchronously emits "message" events in the...

core/promise - Archive of obsolete content
s defer function, which is where all promises ultimately come from. lets see the implementation of readasync that we used in several of the examples above: const { defer } = require('sdk/core/promise'); function readasync(url) { var deferred = defer(); let xhr = new xmlhttprequest(); xhr.open("get", url, true); xhr.onload = function() { deferred.resolve(xhr.responsetext); }; xhr.onerror = function(event) { deferred.reject(event); }; xhr.send(); return deferred.promise; } so defer returns an object that contains a promise and two resolve, reject functions that can be used to resolve / reject that promise. note: a promise can be rejected or resolved only once. all subsequent attempts to either reject it or resolve it will be ignored. another simple example may be a de...

Canvas code snippets - Archive of obsolete content
(); remotecanvas.load(); convert image files to base64 strings the following code gets a remote image and converts its content to data uri scheme. ...

Rosetta - Archive of obsolete content
getsource(oscript) : createscript(oscript); } } function parsedocument () { for ( var ...

Displaying web content in an extension without security issues - Archive of obsolete content
linkinbrowser(event.target.href); } safe html manipulation functions when it comes to displaying the data, it is tempting to generate some html code and to insert it into the document via innerhtml. and scripts won’t run anyway when inserted via innerhtml, right? well, not quite. it is right that <script>alert('xss')</script> won’t run if inserted via innerhtml. but <img src="does_not_exist" onerror="alert('xss')"> for example will still run javascript code, and there are many more possibilities. so properly sanitizing input is still required when using innerhtml and it is far from trivial. it is much easier to use dom manipulation methods that won’t have unexpected side-effects. for example, your template document might have this code: <style type="text/css"> #entrytemplate { display: n...

How to convert an overlay extension to restartless - Archive of obsolete content
ch it from an interface: const xmlhttprequest = components.constructor("@mozilla.org/xmlextras/xmlhttprequest;1", "nsixmlhttprequest"); here's how to load a file using it: function loadfile(url,type,returnresult) { var request = new xmlhttprequest(); request.open("get", url, true); // async=true request.responsetype = type; request.onerror = function(event) { logerrormessage("error attempting to load: " + url); returnresult(null); }; request.onload = function(event) { if (request.response) returnresult(request.response); else request.onerror(event); }; request.send(); } loadfile("chrome://myaddon/content/filename.ext",datatype,function(data) { /* do stuff w...

Index - Archive of obsolete content
red in different ways for different xul input elements as listed below: 966 onclick xul attributes, xul reference no summary! 967 onclosetab xul attributes, xul reference no summary! 968 oncommand xul attributes, xul reference no summary! 969 oncommandupdate xul attributes, xul reference no summary! 970 onerror xul attributes, xul reference no summary! 971 onerrorcommand xul attributes, xul reference no summary! 972 oninput xul attributes, xul reference no summary! 973 onload xul attributes, xul reference no summary! 974 onnewtab xul attributes, xul reference no summary! 975 onpaneload xul attrib...

Migrate apps from Internet Explorer to Mozilla - Archive of obsolete content
ds and properties for mozilla's xmlhttprequest. table 7. xmlhttprequest methods and properties name description void abort() stops the request if it is still running. string getallresponseheaders() returns all response headers as one string. string getresponseheader(string headername) returns the value of the specified header. functionref onerror if set, the references function will be called whenever an error occurs during the request. functionref onload if set, the references function will be called when the request completes successfully and the response has been received. use when an asynchronous request is used. void open (string http_method, string url) void open (string http_method, string url, bool...

Attribute (XUL) - Archive of obsolete content
t minresultsforpopup minwidth mode modifiers mousethrough movetoclick multiline multiple name negate newlines next noautofocus noautohide noinitialfocus nomatch norestorefocus object observes onbeforeaccept onbookmarkgroup onchange onclick onclosetab oncommand oncommandupdate ondialogaccept ondialogcancel ondialogclosure ondialogextra1 ondialogextra2 ondialoghelp onerror onerrorcommand onextra1 onextra2 oninput onload onnewtab onpageadvanced onpagehide onpagerewound onpageshow onpaneload onpopuphidden onpopuphiding onpopupshowing onpopupshown onsearchcomplete onselect ontextcommand ontextentered ontextrevert ontextreverted onunload onwizardback onwizardcancel onwizardfinish onwizardnext open ordinal orient pack pageid pageincrement...

Index - Archive of obsolete content
el xul attributes, xul reference no summary! 225 ondialogdisclosure xul attributes, xul reference no summary! 226 ondialogextra1 xul attributes, xul reference no summary! 227 ondialogextra2 xul attributes, xul reference no summary! 228 ondialoghelp xul attributes, xul reference no summary! 229 onerror xul attributes, xul reference no summary! 230 onerrorcommand xul attributes, xul reference no summary! 231 onextra1 xul attributes, xul reference no summary! 232 onextra2 xul attributes, xul reference no summary! 233 oninput xul attributes, xul reference no summary! 234 onload xul attribut...

image - Archive of obsolete content
e src attribute can be used to specify the url of the image. more information is available in the xul tutorial. note: prior to gecko 8.0, images did not shrink down with the same ratio in both directions when specifying maximum sizes using maxheight or maxwidth. the new behavior aligns more with the html <img> element and shrinks both the width and height down proportionally. attributes onerror, onload, src, validate properties accessibletype, src style classes alert-icon, error-icon, message-icon, question-icon examples <image src='firefoxlogo.png' width='135' height='130'/> attributes onerror type: script code this event is sent to an image element when an error occurs loading the image. image.onload type: script code this event handler will be calle...

Browser Detection and Cross Browser Support - Archive of obsolete content
e that users of browsers which do not support the level of javascript used in your content to turn off javascript in order to be able to use your content. you can do this by providing an error message for users of older browsers as well as alternative content contained in noscript tags. <html> <head> <title>noscript</title> </head> <body> <script language="javascript"> window.onerror = function () { // redirect user to a page describing the limitations // of their browser and requesting that they turn off // javascript in order to view your site. } // netscape navigator 4 will throw an error // on any javascript which attempts to use // try ... catch exception processing. try { // code to implement fan...

RDF in Mozilla FAQ - Archive of obsolete content
allows you to spy on a datasource's progress. the following code illustrates its usage: // this is the object that will observe the rdf/xml load's progress var observer = { onbeginload: function(asink) {}, oninterrupt: function(asink) {}, onresume: function(asink) {}, onendload: function(asink) { asink.removexmlsinkobserver(this); alert("done!"); }, onerror: function(asink, astatus, aerrormsg) { alert("error! " + aerrormsg); } }; // get the rdf service var rdf = components .classes["@mozilla.org/rdf/rdf-service;1"] .getservice(components.interfaces.nsirdfservice); // get the datasource. var ds = rdf.getdatasource("http://www.mozilla.org/some-rdf-file.rdf"); // now see if it's loaded or not... var remote = ds.queryinterface(components.int...

Async scripts for asm.js - Game development
ild(script); both are counted as 'inline' scripts and get compiled and then run immediately. what if your code is in a js string? instead of using eval or innerhtml, both of which trigger synchronous compilation, you should use a blob with an object url: var blob = new blob([codestring]); var script = document.createelement('script'); var url = url.createobjecturl(blob); script.onload = script.onerror = function() { url.revokeobjecturl(url); }; script.src = url; document.body.appendchild(script); the setting of src rather than innerhtml is what makes this script async. ...

Handling common JavaScript problems - Learn web development
function returns false, then we run the code inside the second part of the conditional — this runs a function called loadscript(), which loads the polyfills into the page, then runs main() after the loading has finished. loadscript() looks like this: function loadscript(src, done) { const js = document.createelement('script'); js.src = src; js.onload = function() { done(); }; js.onerror = function() { done(new error('failed to load script ' + src)); }; document.head.appendchild(js); } this function creates a new <script> element, then sets its src attribute to the path we specified as the first argument ('polyfills.js' when we called it in the code above). when it has loaded, we run the function we specified as the second argument (main()). if an error occurs in the lo...

HTMLIFrameElement.executeScript()
of the browser api requires a privileged app, and browser and/or embed-apps permissions, depending on what you want to do. see using the browser api for more details. syntax var mydomrequest = instanceofhtmliframeelement.executescript(script, options); return value a domrequest object that returns an onsuccess handler if the script is successfully executed against the loaded content, or an onerror handler if not. parameters script the script to be executed. options optional optionally, you can provide an origin or url for the script to be executed against. it's recommended that you include an origin or url, in order to ensure that the script is being executed in the expected context: origin: an origin, e.g. http://example.com url: a url, e.g. http://example.com/index.html ...

HTMLIFrameElement.getMuted()
browser <iframe> is currently muted. syntax there are two versions of this method, a callback version: var request = instanceofhtmliframeelement.getmuted(); and a promise version: instanceofhtmliframeelement.getmuted().then(function(muted) { ... }); returns callback version: a domrequest that represents the get muted request. it has an onsuccess handler to handle the success case, and an onerror handler to handle the failure case. the muted value is available in the request.result property, and is a boolean value — true means muted, and false means unmuted. promise version: a promise that resolves with the muted value — a boolean where true means muted, and false means unmuted. parameters none. example callback version: var browser = document.queryselector('iframe'); var requ...

HTMLIFrameElement.getScreenshot()
ms (this delay is defined by the gecko dom.browserelement.maxscreenshotdelayms preference). syntax var instanceofdomrequest = instanceofhtmliframeelement.getscreenshot(maxwidth, maxheight, mimetype); returns a domrequest for handling the screenshot request. its request.onsuccess handler handles the success case (the screenshot is contained in request.result as a blob object), and its request.onerror handler handles the failure case. parameters maxwidth a number representing the maximum width of the screenshot in device pixels. maxheight a number representing the maximum height of the screenshot in device pixels. mimetype optional a mime type specifying the format of the image to be returned; if not specified, the default used is image/jpeg. use image/png to capture the alpha channel...

HTMLIFrameElement.getVolume()
volume of the browser <iframe>. syntax there are two versions of this method, a callback version: var request = instanceofhtmliframeelement.getvolume(); and a promise version: instanceofhtmliframeelement.getvolume().then(function(volume) { ... }); returns callback version: a domrequest that represents the get volume request. it has an onsuccess handler to handle the success case, and an onerror handler to handle the failure case. the volume value is available in the request.result property, and is a floating point number between 0 and 1. promise version: a promise that resolves with the volume value — a floating point number between 0 and 1. parameters none. example callback version: var browser = document.queryselector('iframe'); var request = browser.getvolume(); request.on...

IPDL Tutorial
t! normal errors should be signaled with a message or return value. note: the following paragraphs are not yet implemented. ipdl tracks all active protocols between two endpoints. if if the child side crashes or becomes hung: any synchronous or rpc messages currently active will return false no further messages will be accepted (c++ methods will return false) each ipdl actor will receive an onerror message deallocpsubprotocol will be called on each manager protocol to deallocate any active subprotocols. when a manager protocol is destroyed, any subprotocols will be notified: no further messages will be accepted deallocpsubprotocol will be called on the manager protocol to deallocate any active subprotocols when the toplevel protocol is destroyed, this is equivalent to shutting down...

Http.jsm
postdata this can be: a string: send it as is an array of parameters: encode as form values null/undefined: no post data. method get, post or put (this is automatically set if postdata exists). onload a function handle to call when the load is complete, it takes two parameters: the responsetext and the xhr object. onerror a function handle to call when an error occurs, it takes three parameters: the error, the responsetext and the xhr object. logger an object that implements the debug and log methods (e.g. log.jsm). headers or post data are given as an array of arrays, for each inner array the first value is the key and the second is the value. for example: [["key1", "value1"], ["key2", "val...

OS.File for the main thread
|data| return promise.then(function onsuccess(bytes) { return loop(pos + bytes); // ... and loop. }); }; let promise = loop(0); // enter the loop. promise = promise.then(function onsuccess() { // once loop is complete, finalize. ...

Examples
the error = ' + uneval(e)); } myimage.onabort = function(e) { loadthisimagepromise.reject('image load was aborted loading path = "' + path + '".'); } myimage.src = path; }); return promise.all(mysubpromises); } catch(ex) { return promise.rej...

Sqlite.jsm
); } catch (err) { // an error occurred. console.log(err); // error, oh noes! if (callback) { callback(err); } } // all accounts returned successfully, so do something with them. console.log(result); // it worked! if (callback) { callback(null, accounts); } note: the then parameters can be anonymous functions (i.e. function() ), and only are labeled as onstatementcomplete and onerror for readability. this example demonstrates retrieving a row without using the onrow function parameter, and instead, using the conn.execute result. this example also demonstrates retrieving the primary key row id of the last inserted row. async function () { try { conn = await sqlite.openconnection({ path: dbfile.path }); let statement = "insert into accounts (username, details) val...

WebRequest.jsm
name string header name, for example "content-type" value string header value, for example "image/png" chrome incompatibilities although this api is modeled on chrome's webrequest extension api, there are some differences. we're working on addressing them, though. filtering by windowid and tabid is not supported. the onauthrequired, onbeforeredirect, and onerroroccurred events are not supported. the "requestbody" instruction in opt_extrainfospec is not supported. redirection is not allowed in onbeforerequest or onheadersreceived, but is allowed in onbeforesendheaders. see bug 1176092. handlerbehaviorchanged() is not supported. requestid is not included in the argument passed to the listener. examples basic examples this example just logs the url ...

JS::CompileOptions
lycompileoptions method description bool mutederrors() const determines if errors are muted. the web platform allows scripts to be loaded from arbitrary cross-origin sources. this allows an attack by which a malicious website loads a sensitive file (say, a bank statement) cross-origin (using the user's cookies), and sniffs the generated syntax errors (via a window.onerror handler) for juicy morsels of its contents. to counter this attack, html5 specifies that script errors should be sanitized ("muted") when the script is not same-origin with the global for which it is loaded. callers should set this flag for cross-origin scripts, and it will be propagated appropriately to child scripts and passed back in jserrorreports. const char *filename() con...

JSErrorReport
column unsigned zero-based column index in line in the source that caused the error. ismuted bool the web platform allows scripts to be loaded from arbitrary cross-origin sources. this allows an attack by which a malicious website loads a sensitive file (say, a bank statement) cross-origin (using the user's cookies), and sniffs the generated syntax errors (via a window.onerror handler) for juicy morsels of its contents. to counter this attack, html5 specifies that script errors should be sanitized ("muted") when the script is not same-origin with the global for which it is loaded. callers should set this flag for cross-origin scripts, and it will be propagated appropriately to child scripts and passed back in jserrorreports. linebuf const char * ...

nsIAbstractWorker
dom/interfaces/threads/nsidomworkers.idlscriptable this interface is an abstract interface used to implement the web workers architecture. 1.0 66 introduced gecko 1.9.1 inherits from: nsidomeventtarget last changed in gecko 1.9.1 (firefox 3.5 / thunderbird 3.0 / seamonkey 2.0) attributes attribute type description onerror nsidomeventlistener the error listener for the worker. see also using web workers nsiworkermessageport nsiworkermessageevent nsiworkerscope nsiworkerglobalscope nsiworker ...

nsIDOMOfflineResourceList
items nsidomofflineresourcelist the list of dynamically-managed entries in the offline resource list. read only. mozlength unsigned long the number of entries in the dynamically managed offline resource list. read only. onchecking nsidomeventlistener an event listener to be called when fetching the application cache manifest and checking for updates. onerror nsidomeventlistener an event listener to be called when an error occurs during the caching process. onnoupdate nsidomeventlistener an event listener to be called when there is no update to download. ondownloading nsidomeventlistener an event listener to be called when resources are being downloaded into the cache. onprogress nsidomeventlistener a...

nsIWorkerGlobalScope
de' of a worker. this interface allows a worker to look up information about itself, as well as to control itself. 1.0 66 introduced gecko 1.9.1 inherits from: nsisupports last changed in gecko 1.9.2 (firefox 3.6 / thunderbird 3.1 / fennec 1.0) attributes attribute type description location nsiworkerlocation read only. navigator nsiworkernavigator read only. onerror nsidomeventlistener self nsiworkerglobalscope returns the global scope object itself. read only. see also using web workers nsiworkermessageport nsiworkermessageevent nsiworkerscope nsiabstractworker nsiworker ...

nsIXMLHttpRequestEventTarget
ent listeners used when uploading data using the xmlhttprequest object. 1.0 66 introduced gecko 1.9.1 inherits from: nsidomeventtarget last changed in gecko 5.0 (firefox 5.0 / thunderbird 5.0 / seamonkey 2.2) attributes attribute type description onabort nsidomeventlistener a javascript function object that gets invoked if the operation is canceled by the user. onerror nsidomeventlistener a javascript function object that gets invoked if the operation fails to complete due to an error. onload nsidomeventlistener a javascript function object that gets invoked when the operation is successfully completed. onloadend nsidomeventlistener a javascript function object that gets invoked when the operation is completed for any reason; it will always follow a an abo...

nsIXMLHttpRequestUpload
this interface provides access to the features needed when uploading data using nsixmlhttprequest. ...

XPCOM Interface Reference
xt2dnsidomchromewindownsidomclientrectnsidomdesktopnotificationnsidomdesktopnotificationcenternsidomelementnsidomeventnsidomeventgroupnsidomeventlistenernsidomeventtargetnsidomfilensidomfileerrornsidomfileexceptionnsidomfilelistnsidomfilereadernsidomfontfacensidomfontfacelistnsidomgeogeolocationnsidomgeopositionnsidomgeopositionaddressnsidomgeopositioncallbacknsidomgeopositioncoordsnsidomgeopositionerrornsidomgeopositionerrorcallbacknsidomgeopositionoptionsnsidomglobalpropertyinitializernsidomhtmlaudioelementnsidomhtmlformelementnsidomhtmlmediaelementnsidomhtmlsourceelementnsidomhtmltimerangesnsidomjswindownsidommousescrolleventnsidommoznetworkstatsnsidommoznetworkstatsdatansidommoznetworkstatsmanagernsidommoztoucheventnsidomnshtmldocumentnsidomnavigatordesktopnotificationnsidomnodensidomoffliner...

XPCOM Interface Reference by grouping
browser autocomplete nsiautocompletecontroller nsiautocompleteinput nsiautocompletesearch console nsiconsolelistener nsiconsolemessage nsiconsoleservice document nsidocshell dom device nsidomgeogeolocation nsidomgeoposition nsidomgeopositionaddress nsidomgeopositioncallback nsidomgeopositioncoords nsidomgeopositionerror nsidomgeopositionerrorcallback nsidomgeopositionoptions nsidomglobalpropertyinitializer element nsidomchromewindow nsidomclientrect nsidomelement nsidomhtmlaudioelement nsidomhtmlformelement nsidomhtmlmediaelement nsidomhtmlsourceelement nsidomhtmltimeranges nsidomjswindow nsidomnode nsidomnshtmldocument nsidomstorageitem nsi...

MailNews fakeserver
use is very small, most people shouldn't have to write an entirely new daemon and handler setup by themselves. that said, someone writing a new test may have to take into account a new handler. a handler will contain the following methods: <caption> handler methods </caption> name arguments returns notes [command] rest of sent line server's response the name is normalized to be uppercase. onerror command, rest of sent line server's response called if handler does not define the command function. onstartup none server's response called when a connection is made. onmultiline sent line server's response or nothing called when in multi-line mode. postcommand server object none called after every command. the server is smart about the responses and will normalize all occurrences of '...

Debugger - Firefox Developer Tools
atement, or a new exception. in those cases the old exception does not continue to propagate; it is discarded.) this handler is not called when unwinding a frame due to an over-recursion or out-of-memory exception. sourcehandler(asuffusionofyellow) this method is never called. if it is ever called, a contradiction has been proven, and the debugger is free to assume that everything is true. onerror(frame,report) spidermonkey is about to report an error inframe.report is an object describing the error, with the following properties: message the fully formatted error message. file if present, the source file name, url, etc. (if this property is present, theline property will be too, and vice versa.) line if present, the source line number at which the error occurred. linet...

AbstractWorker - Web APIs
ctworker interface of the web workers api is an abstract interface that defines properties and methods that are common to all types of worker, including not only the basic worker, but also serviceworker and sharedworker. as an abstract class, you don't directly interact with abstractworker. properties the abstractworker interface doesn't inherit any properties. event handlers abstractworker.onerror an eventlistener which is invoked whenever an errorevent of type error bubbles through the worker. methods the abstractworker interface doesn't implement or inherit any methods. example as an abstract interface, you won't directly use abstractworker in your code. instead, you'll interact with either worker or sharedworker, both of which inherit the properties of abstractworker. this code s...

Accelerometer.Accelerometer() - Web APIs
stent with the policies set on your server. this is not something that would ever be shown to a user. see feature-policy for implementation instructions. syntax var accelerometer = new accelerometer([options]) parameters options optional options are as follows: frequency: the desired number of times per second a sample should be taken, meaning the number of times per second that sensor.onerror will be called. a whole number or decimal may be used, the latter for frequencies less than a second. the actual reading frequency depends device hardware and consequently may be less than requested. referenceframe: either 'device' or 'screen'. the default is 'device'. specifications specification status comment generic sensor api candidate recommendation de...

AddressErrors.organization - Web APIs
an object based on addresserrors includes an organization property when the address's organization property couldn't be validated. the returned string explains the error and should offer suggestions for how to correct it. syntax var organizationerror = addresserrors.organization; value if the value specified in the paymentaddress object's organization property could not be validated, this property contains a domstring offering a human-readable explanation of the validation error and offers suggestions for correcting it. for example, if validation simply ensures that only permitted characters are included in the organization's name, this might return a string such as "the organization name may only contain the letters a-z, digits, spaces, and commas." if the organization value was validated...

AddressErrors.region - Web APIs
an object based on addresserrors includes a region property when the address's region property couldn't be validated. the returned string explains the error and should offer suggestions for how to correct it. syntax var regionerror = addresserrors.region; value if the value specified in the paymentaddress object's region property could not be validated, this property contains a domstring offering a human-readable explanation of the validation error and offers suggestions for correcting it. if the region value was validated successfully, this property is not included in the addresserrors object. specifications specification status comment payment request apithe definition of 'addresserrors.region' in that specification. candidate recommendation initial definit...

AmbientLightSensor.illuminance - Web APIs
ng that would ever be shown to a user. see feature-policy for implementation insfructions. syntax var level = ambientlightsensor.illuminance value a number indicating the current light level in lux. example if ( 'ambientlightsensor' in window ) { const sensor = new ambientlightsensor(); sensor.onreading = () => { console.log('current light level:', sensor.illuminance); }; sensor.onerror = (event) => { console.log(event.error.name, event.error.message); }; sensor.start(); } specifications specification status comment generic sensor api candidate recommendation defines sensors in general. ambient light sensorthe definition of 'illuminance' in that specification. candidate recommendation ...

AmbientLightSensor - Web APIs
bientlightsensor() creates a new ambientlightsensor object. properties ambientlightsensor.illuminance returns the current light level in lux of the ambient light level around the hosting device. example if ( 'ambientlightsensor' in window ) { const sensor = new ambientlightsensor(); sensor.onreading = () => { console.log('current light level:', sensor.illuminance); }; sensor.onerror = (event) => { console.log(event.error.name, event.error.message); }; sensor.start(); } specifications specification status comment generic sensor api candidate recommendation defines sensors in general. ambient light sensorthe definition of 'ambientlightsensor' in that specification. candidate recommendation ...

CSS.registerProperty() - Web APIs
ing defined. syntax optional a domstring representing the expected syntax of the defined property. defaults to "*". inherits a boolean value defining whether the defined property should be inherited (true), or not (false). defaults to false. initialvalue optional a domstring representing the initial value of the defined property. return value undefined. exceptions invalidmodificationerror the given name has already been registered. syntaxerror the given name isn't a valid custom property name (starts with two dashes, e.g. --foo). typeerror the required name and/or inherits dictionary members were not provided. examples the following will register a custom property, --my-color, using registerproperty(), as a color, give it a default value, and have it not inherit its value:...

Clipboard.write() - Web APIs
key of the object passed to the clipboarditem constructor indicates the content type, the value indicates the content. the content could be a text or even a blob (e.g. for copying images to the clipboard). then write() is called, specifying both a fulfilment function and an error function. example of copying canvas contents to the clipboard function copycanvascontentstoclipboard(canvas, ondone, onerror) { canvas.toblob(function (blob) { let data = [new clipboarditem({ [blob.type]: blob })]; navigator.clipboard.write(data).then(function () { ondone(); }, function (err) { onerror(err); }) }); } note: you can only pass in one clipboard item at a time. specifications specification status comment clipboard api and eventsthe definition of ...

DOMError - Web APIs
or the string contains invalid characters. nomodificationallowederror the object can not be modified. notfounderror the object can not be found here. notsupportederror the operation is not supported invalidstateerror the object is in an invalid state. syntaxerror the string did not match the expected pattern. invalidmodificationerror the object can not be modified in this way. namespaceerror the operation is not allowed by namespaces in xml invalidaccesserror the object does not support the operation or argument. typemismatcherror the type of the object does not match the expected type. securityerror the operation is insecure. networkerror a network error occurred...

DirectoryReaderSync - Web APIs
m urls. var paths = []; function getallentries(dirreader) { var entries = dirreader.readentries(); for (var i = 0, entry; entry = entries[i]; ++i) { // stash this entry's filesystem in url paths.push(entry.tourl()); // if this is a directory, traverse. if (entry.isdirectory) { getallentries(entry.createreader()); } } } // forward the error to main app. function onerror(e) { postmessage('error: ' + e.tostring()); } self.onmessage = function(e) { var data = e.data; // ignore everything else except our 'list' command. if (!data.cmd || data.cmd != 'list') { return; } try { var fs = requestfilesystemsync(temporary, 1024*1024 /*1mb*/); getallentries(fs.root.createreader()); self.postmessage({entries: paths}); } catch (e) { onerr...

Document - Web APIs
art event is sent, indicating that a css animation has started playing. globaleventhandlers.onauxclick an eventhandler called when an auxclick event is sent, indicating that a non-primary button has been pressed on an input device (e.g. a middle mouse button). globaleventhandlers.onblur is an eventhandler representing the code to be called when the blur event is raised. globaleventhandlers.onerror is an onerroreventhandler representing the code to be called when the error event is raised. globaleventhandlers.onfocus is an eventhandler representing the code to be called when the focus event is raised. globaleventhandlers.oncancel is an eventhandler representing the code to be called when the cancel event is raised. globaleventhandlers.oncanplay is an eventhandler representing the cod...

Element: error event - Web APIs
the error event is fired on an element object when a resource failed to load, or can't be used. for example, if a script has an execution error or an image can't be found or is invalid. bubbles no cancelable no interface event or uievent event handler property onerror the event object is a uievent instance if it was generated from a user interface element, or an event instance otherwise. examples live example html <div class="controls"> <button id="img-error" type="button">generate image error</button> <img class="bad-img" /> </div> <div class="event-log"> <label>event log:</label> <textarea readonly class="event-log-contents" rows="8" cols="30"></textarea> </div> css body { display: grid; grid-template-areas: "control ...

Element.innerHTML - Web APIs
s case although this may look like a cross-site scripting attack, the result is harmless. html5 specifies that a <script> tag inserted with innerhtml should not execute. however, there are ways to execute javascript without using <script> elements, so there is still a security risk whenever you use innerhtml to set strings over which you have no control. for example: const name = "<img src='x' onerror='alert(1)'>"; el.innerhtml = name; // shows the alert for that reason, it is recommended that you do not use innerhtml when inserting plain text; instead, use node.textcontent. this doesn't parse the passed content as html, but instead inserts it as raw text. warning: if your project is one that will undergo any form of security review, using innerhtml most likely will result in your code bein...

Element - Web APIs
iss the current open dialog. for example, the browser might fire this event when the user presses the esc key or clicks a "close dialog" button which is part of the browser's ui. also available via the oncancel property. error fired when a resource failed to load, or can't be used. for example, if a script has an execution error or an image can't be found or is invalid. also available via the onerror property. scroll fired when the document view or an element has been scrolled. also available via the onscroll property. select fired when some text has been selected. also available via the onselect property. show fired when a contextmenu event was fired on/bubbled to an element that has a contextmenu attribute. also available via the onshow property. wheel fired when the user rotat...

EventSource: error event - Web APIs
the error event of the eventsource api is fired when a connection with an event source fails to be opened. bubbles no cancelable no interface event or errorevent event handler property eventsource.onerror examples var evtsource = new eventsource('sse.php'); // addeventlistener version evtsource.addeventlistener('error', (e) => { console.log("an error occurred while attempting to connect."); }); // onerror version evtsource.onerror = (e) => { console.log("an error occurred while attempting to connect."); }; specifications specification status html living standardthe definition of 'error event' in that specification. living standard ...

EventSource - Web APIs
representing the state of the connection. possible values are connecting (0), open (1), or closed (2). eventsource.url read only a domstring representing the url of the source. eventsource.withcredentials read only a boolean indicating whether the eventsource object was instantiated with cross-origin (cors) credentials set (true), or not (false, the default). event handlers eventsource.onerror is an eventhandler called when an error occurs and the error event is dispatched on an eventsource object. eventsource.onmessage is an eventhandler called when a message event is received, that is when a message is coming from the source. eventsource.onopen is an eventhandler called when an open event is received, that is when the connection was just opened. methods this interface also in...

FileException - Web APIs
ter and adds several new error codes. basic concepts synchronous apis do not have error callbacks, which makes it difficult to catch errors. the added complexity of using webworkers with this api makes debugging even more challenging. to simplify things a bit, wrap your worker code in a try/catch. when errors occur, forward them to the main app using postmessage() as in the following: function onerror(e) { postmessage('error:' + e.tostring()); } try { //error is thrown if "log.txt" already exists. var fileentry = fs.root.getfile('log.txt', {create: true, exclusive:true}0; } catch (e) { onerrror(e); } the sample code was borrowed from html5rocks attribute attribute type description code unsigned short the most appropriate error code for the condition...

FileReader: error event - Web APIs
the error event is fired when the read failed due to an error (for example, because the file was not found or not readable). ...

FileSystemDirectoryEntry - Web APIs
esystem || window.webkitrequestfilesystem; window.directoryentry = window.directoryentry || window.webkitdirectoryentry; ... function onfs(fs){ fs.root.getdirectory('documents', {create:true}, function(directoryentry){ //directoryentry.isfile === false //directoryentry.isdirectory === true //directoryentry.name === 'documents' //directoryentry.fullpath === '/documents' }, onerror); } // opening a file system with temporary storage window.requestfilesystem(temporary, 1024*1024 /*1mb*/, onfs, onerror); properties this interface has no properties of its own, but inherits properties from its parent interface, filesystementry. methods this interface inherits methods from its parent interface, filesystementry. createreader() creates a filesystemdirectoryreader objec...

FileSystemEntry - Web APIs
ame. // taking care of the browser-specific prefixes. window.requestfilesystem = window.requestfilesystem || window.webkitrequestfilesystem; ... // opening a file system with temporary storage window.requestfilesystem(temporary, 1024*1024 /*1mb*/, function(fs) { fs.root.getfile('log.txt', {}, function(fileentry) { fileentry.remove(function() { console.log('file removed.'); }, onerror); }, onerror); }, onerror); properties this interface provides the following properties. filesystem read only a filesystem object representing the file system in which the entry is located. fullpath read only a usvstring object which provides the full, absolute path from the file system's root to the entry; it can also be thought of as a path which is relative to the root directory,...

FileSystemFileEntry.file() - Web APIs
le and calls a specified callback function with the received text (in a string object) once the read is completed. if an error occurs, a specified (optional) error callback is called. function readfile(entry, successcallback, errorcallback) { entry.file(function(file) { let reader = new filereader(); reader.onload = function() { successcallback(reader.result); }; reader.onerror = function() { errorcallback(reader.error); } reader.readastext(file); }, errorcallback); } this function calls file(), specifying as its success callback a method which proceeds to use a filereader to read the file as text. the filereader's load event handler is set up to deliver the loaded string to the successcallback specified when the readfile() method was called; similarl...

FileSystemFileEntry - Web APIs
blob, appending text to it, and passing the blob to filewriter.write(). function oninitfs(fs) { fs.root.getfile('log.txt', {create: true}, function(fileentry) { // create a filewriter object for our filesystemfileentry (log.txt). fileentry.createwriter(function(filewriter) { filewriter.onwriteend = function(e) { console.log('write completed.'); }; filewriter.onerror = function(e) { console.log('write failed: ' + e.tostring()); }; // create a new blob and write it to log.txt. var bb = new blobbuilder(); bb.append('meow'); filewriter.write(bb.getblob('text/plain')); }, errorhandler); }, errorhandler); } window.requestfilesystem(window.temporary, 1024*1024, oninitfs, errorhandler); specifications speci...

Geolocation.getCurrentPosition() - Web APIs
the geolocation.getcurrentposition() method is used to get the current position of the device. syntax navigator.geolocation.getcurrentposition(success[, error[, [options]]) parameters success a callback function that takes a geolocationposition object as its sole input parameter. error optional an optional callback function that takes a geolocationpositionerror object as its sole input parameter. options optional an optional positionoptions object. options includes: maximumage: integer (milliseconds) | infinity - maximum cached position age. timeout: integer (milliseconds) - amount of time before the error callback is invoked, if 0 it will never invoke. enablehighaccuracy: false | true examples var options = { enablehighaccuracy: true, timeout: 5000, maximumage...

Geolocation.watchPosition() - Web APIs
be called automatically each time the position of the device changes. you can also, optionally, specify an error handling callback function. syntax navigator.geolocation.watchposition(success[, error[, options]]) parameters success a callback function that takes a geolocationposition object as an input parameter. error optional an optional callback function that takes a geolocationpositionerror object as an input parameter. options optional an optional positionoptions object that provides configuration options for the location watch. return value an integer id that identifies the registered handler. the id can be passed to the geolocation.clearwatch() to unregister the handler. examples var id, target, options; function success(pos) { var crd = pos.coords; if (target.latitu...

Using the Geolocation API - Web APIs
ur latitude and longitude } you can however get a number of other bits of information from a geolocationcoordinates object, including altitude, speed, what direction the device is facing, and an accuracy measure of the altitude, longitude, and latitude data. handling errors the error callback function, if provided when calling getcurrentposition() or watchposition(), expects a geolocationpositionerror object instance as its first parameter. this object type contains two properties, a code indicating what type of error has been returned, and a human-readable message that describes what the error code means. you could use it like so: function errorcallback(error) { alert(`error(${error.code}): ${error.message}`); }; examples in the following example the geolocation api is used to retrieve...

GlobalEventHandlers - Web APIs
art event is sent, indicating that a css animation has started playing. globaleventhandlers.onauxclick an eventhandler called when an auxclick event is sent, indicating that a non-primary button has been pressed on an input device (e.g. a middle mouse button). globaleventhandlers.onblur is an eventhandler representing the code to be called when the blur event is raised. globaleventhandlers.onerror is an onerroreventhandler representing the code to be called when the error event is raised. globaleventhandlers.onfocus is an eventhandler representing the code to be called when the focus event is raised. globaleventhandlers.oncancel is an eventhandler representing the code to be called when the cancel event is raised. globaleventhandlers.oncanplay is an eventhandler representing the cod...

HTMLCanvasElement - Web APIs
rol to an offscreencanvas object, either on the main thread or on a worker. obsolete methods htmlcanvaselement.mozgetasfile() returns a file object representing the image contained in the canvas; this file is a memory-based file, with the specified name. if type is not specified, the image type is image/png. events listen to these events using addeventlistener(). webglcontextcreationerror fired if the user agent is unable to create a webglrenderingcontext or webgl2renderingcontext context. webglcontextlost fired if the user agent detects that the drawing buffer associated with a webglrenderingcontext or webgl2renderingcontext object has been lost. webglcontextrestored fired if the user agent restores the drawing buffer for a webglrenderingcontext or webgl2renderingcontext obj...

HTMLImageElement.complete - Web APIs
lete property before attempting to do its work. this is demonstrated in the code below. let lightboxelem = document.queryselector("#lightbox"); let lightboximgelem = lightboxelem.queryselector("img"); let lightboxcontrolselem = lightboxelem.queryselector(".toolbar"); async function loadimage(url, elem) { return new promise((resolve, reject) => { elem.onload = () => resolve(elem); elem.onerror = reject; elem.src = url; }); } async function lightbox(url) { lightboxelem.style.display = "block"; await loadimage("https://somesite.net/huge-image.jpg", lightboximgelem); lightboxcontrolselem.disabled = false; } /* ... */ function fixredeyecommand() { if (lightboxelem.style.display === "block" && lightboximgelem.complete) { fixredeye(lightboximgelem); } else { /* can...

HTMLImageElement - Web APIs
s properties from its parent, htmlelement. htmlimageelement.decode() returns a promise that resolves when the image is decoded and it's safe to append the image to the dom. this prevents rendering of the next frame from having to pause to decode the image, as would happen if an undecoded image were added to the dom. errors if an error occurs while trying to load or render the image, and an onerror event handler has been configured to handle the error event, that event handler will get called. this can happen in a number of situations, including: the src attribute is empty or null. the specified src url is the same as the url of the page the user is currently on. the specified image is corrupted in some way that prevents it from being loaded. the specified image's metadata is corrupte...

HTMLMediaElement.error - Web APIs
xamining this object. syntax var myerror = htmlmediaelement.error; value a mediaerror object describing the most recent error to occur on the media element or null if no errors have occurred. example this example establishes a video element and adds an error handler to it; the error handler simply logs the details to console. var videoelement = document.createelement('video'); videoelement.onerror = function() { console.log("error " + videoelement.error.code + "; details: " + videoelement.error.message); } videoelement.src = "https://example.com/bogusvideo.mp4"; specifications specification status comment html living standardthe definition of 'htmlmediaelement.error' in that specification. living standard html5the definition of 'htmlmediaelemen...

HTMLMediaElement: error event - Web APIs
the error event is fired when the resource could not be loaded due to an error (for example, a network connectivity problem). ...

Ajax navigation example - Web APIs
function filterurl (surl, sviewmode) { return surl.replace(rsearch, "") + ("?" + surl.replace(rhost, "&").replace(rview, sviewmode ? ...

IDBDatabase.close() - Web APIs
is connection once this method is called. methods that create transactions throw an exception if a closing operation is pending. note: this feature is available in web workers. syntax idbdatabase.close(); example // let us open our database var dbopenrequest = window.indexeddb.open("todolist", 4); // opening a database. // create event handlers for both success and failure of dbopenrequest.onerror = function(event) { note.innerhtml += "<li>error loading database.</li>"; }; dbopenrequest.onsuccess = function(event) { note.innerhtml += "<li>database initialised.</li>"; // store the result of opening the database in the db variable. db = dbopenrequest.result; // now let"s close the database again! db.close(); }; specification specification status comment ...

IDBDatabase: close event - Web APIs
database connection is unexpectedly closed. this could happen, for example, if the underlying storage is removed or if the user clears the database in the browser's history preferences. note that it is not fired if the database connection is closed normally using idbdatabase.close(). ...

IDBDatabase.createObjectStore() - Web APIs
tabase var request = window.indexeddb.open("todolist", 4); // this handler is called when a new version of the database // is created, either when one has not been created before // or when a new version number is submitted by calling // window.indexeddb.open(). // this handler is only supported in recent browsers. ...

IDBDatabase.name - Web APIs
database connection being opened, the resulting idbdatabase object being stored in a db variable, and the name property then being logged. for a full example, see our to-do notifications app (view example live). // let us open our database var dbopenrequest = window.indexeddb.open("todolist", 4); // these two event handlers act on the database being // opened successfully, or not dbopenrequest.onerror = function(event) { note.innerhtml += '<li>error loading database.</li>'; }; dbopenrequest.onsuccess = function(event) { note.innerhtml += '<li>database initialised.</li>'; // store the result of opening the database in the db variable. this is used a lot below db = dbopenrequest.result; // this line will log the name of the database, which should be "todolist" console.log(db.name)...

IDBDatabase.objectStoreNames - Web APIs
his feature is available in web workers. syntax var list[] = idbdatabase.objectstorenames; value a domstringlist containing a list of the names of the object stores currently in the connected database. example // let us open our database var dbopenrequest = window.indexeddb.open("todolist", 4); // these two event handlers act on the database being opened successfully, or not dbopenrequest.onerror = function(event) { note.innerhtml += '<li>error loading database.</li>'; }; dbopenrequest.onsuccess = function(event) { note.innerhtml += '<li>database initialised.</li>'; // store the result of opening the database in the db variable. this is used a lot below db = dbopenrequest.result; // this line will log the version of the connected database, which should be // an object that ...

IDBDatabase.transaction() - Web APIs
duplicate items not allowed.</li>'; }; // you would then go on to do something to this database // via an object store var objectstore = transaction.objectstore("todolist"); // etc. specification specification status comment indexed database api 2.0the definition of 'transaction()' in that...

IDBDatabase.version - Web APIs
ed, this attribute is an empty string. note: this feature is available in web workers. syntax var myinteger = idbdatabase.version; value an integer containing the version of the connected database. example // let us open our database var dbopenrequest = window.indexeddb.open("todolist", 4); // these two event handlers act on the database // being opened successfully, or not dbopenrequest.onerror = function(event) { note.innerhtml += '<li>error loading database.</li>'; }; dbopenrequest.onsuccess = function(event) { note.innerhtml += '<li>database initialised.</li>'; // store the result of opening the database in the db variable. this is used a lot below db = dbopenrequest.result; // this line will log the version of the connected database, which should be "4" console.log(db...

IDBFactory.deleteDatabase() - Web APIs
rsion 26, you can include a non-standard optional storage parameter that specifies whether you want to delete a permanent (the default value) indexeddb, or an indexeddb in temporary storage (aka shared pool.) return value a idbopendbrequest on which subsequent events related to this request are fired. example var dbdeleterequest = window.indexeddb.deletedatabase("todolist"); dbdeleterequest.onerror = function(event) { console.log("error deleting database."); }; dbdeleterequest.onsuccess = function(event) { console.log("database deleted successfully"); console.log(event.result); // should be undefined }; specifications specification status comment indexed database api draftthe definition of 'deletedatabase()' in that specification. recommendation ...

IDBFactory.open() - Web APIs
this is used a lot later on, for opening // transactions and suchlike. db = dbopenrequest.result; }; specifications specificatio...

IDBFactory - Web APIs
this is used a lot later on, for opening transactions and suchlike. db = dbopenrequest.result; }; specifications specification status comment ind...

IDBMutableFile - Web APIs
jects are bound to a fake file system built on top of indexeddb, such an object is created using the idbdatabase.createmutablefile method. properties mutablefile.name read only the name of the handled file. mutablefile.type read only the mime type of the handled file. events handler mutablefile.onabort the abort event is triggered each time the handled file is aborted. mutablefile.onerror the error event is triggered each time something goes wrong. methods mutablefile.open() returns a lockedfile object to read or write the associated file safely. mutablefile.getfile() returns a domrequest object. in case of success, the request's result is a file object representing a snapshot of the handled file. specifications not part of any specification at present. see also lo...

IDBObjectStore.add() - Web APIs
duplicate items not allowed.</li>'; }; // create an object store on the transaction var objectstore = transaction.objectstore("todolist"); // make a request to add our newitem object to the object store var objectstorerequest = objectstore.add(newitem[0]); objectstorerequest.onsuccess = function(event...

IDBObjectStore.autoIncrement - Web APIs
duplicate items not allowed.</li>'; }; // create an object store on the transaction var objectstore = transaction.objectstore("todolist"); console.log(objectstore.autoincrement); // make a request to add our newitem object to the object store var objectstorerequest = objectstore.add(newitem[0]); o...

IDBObjectStore.clear() - Web APIs
form the object store cleardata(); }; function cleardata() { // open a read/write db transaction, ready for clearing the data var transaction = db.transaction(["todolist"], "readwrite"); // report on the success of the transaction completing, when everything is done transaction.oncomplete = function(event) { note.innerhtml += '<li>transaction completed.</li>'; }; transaction.onerror = function(event) { note.innerhtml += '<li>transaction not opened due to error: ' + transaction.error + '</li>'; }; // create an object store on the transaction var objectstore = transaction.objectstore("todolist"); // make a request to clear all the data out of the object store var objectstorerequest = objectstore.clear(); objectstorerequest.onsuccess = function(event) { /...

IDBObjectStore.delete() - Web APIs
rd from the database deletedata(); }; function deletedata() { // open a read/write db transaction, ready for deleting the data var transaction = db.transaction(["todolist"], "readwrite"); // report on the success of the transaction completing, when everything is done transaction.oncomplete = function(event) { note.innerhtml += '<li>transaction completed.</li>'; }; transaction.onerror = function(event) { note.innerhtml += '<li>transaction not opened due to error: ' + transaction.error + '</li>'; }; // create an object store on the transaction var objectstore = transaction.objectstore("todolist"); // make a request to delete the specified record out of the object store var objectstorerequest = objectstore.delete("walk dog"); objectstorerequest.onsuccess = fun...

IDBObjectStore.get() - Web APIs
e data from the database getdata(); }; function getdata() { // open a read/write db transaction, ready for retrieving the data var transaction = db.transaction(["todolist"], "readwrite"); // report on the success of the transaction completing, when everything is done transaction.oncomplete = function(event) { note.innerhtml += '<li>transaction completed.</li>'; }; transaction.onerror = function(event) { note.innerhtml += '<li>transaction not opened due to error: ' + transaction.error + '</li>'; }; // create an object store on the transaction var objectstore = transaction.objectstore("todolist"); // make a request to get a record by key from the object store var objectstorerequest = objectstore.get("walk dog"); objectstorerequest.onsuccess = function(event) ...

IDBObjectStore.indexNames - Web APIs
duplicate items not allowed.</li>'; }; // create an object store on the transaction var objectstore = transaction.objectstore("todolist"); console.log(objectstore.indexnames); // make a request to add our newitem object to the object store var objectstorerequest = objectstore.add(newitem[0]); object...

IDBObjectStore.keyPath - Web APIs
duplicate items not allowed.</li>'; }; // create an object store on the transaction var objectstore = transaction.objectstore("todolist"); console.log(objectstore.keypath); // make a request to add our newitem object to the object store var objectstorerequest = objectstore.add(newitem[0]); objectsto...

IDBObjectStore.name - Web APIs
duplicate items not allowed.</li>'; }; // create an object store on the transaction var objectstore = transaction.objectstore("todolist"); console.log(objectstore.name); // make a request to add our newitem object to the object store var objectstorerequest = objectstore.add(newitem[0]); objectstorer...

IDBObjectStore.transaction - Web APIs
duplicate items not allowed.</li>'; }; // create an object store on the transaction var objectstore = transaction.objectstore("todolist"); console.log(objectstore.transaction); // make a request to add our newitem object to the object store var objectstorerequest = objectstore.add(newitem[0]); obj...

IDBTransaction.abort() - Web APIs
duplicate items not allowed.</li>'; }; // create an object store on the transaction var objectstore = transaction.objectstore("todolist"); // add our newitem object to the object store var objectstorerequest = objectstore.add(newitem[0]); objectstorerequest.onsuccess = function(event) { // repor...

IDBTransaction.commit() - Web APIs
invalidstateerror the transaction state is not active. examples // open a read/write db transaction, ready for adding the data var transaction = db.transaction(["mydb"], "readwrite"); // report on the success of opening the transaction transaction.oncomplete = function(event) { note.innerhtml += '<li>transaction completed: database modification finished.</li>'; }; transaction.onerror = function(event) { note.innerhtml += '<li>transaction not opened due to error. duplicate items not allowed.</li>'; }; // create an object store on the transaction var objectstore = transaction.objectstore("myobjstore"); // add our newitem object to the object store var objectstorerequest = objectstore.add(newitem[0]); objectstorerequest.onsuccess = function(event) { // report the success ...

IDBTransaction.db - Web APIs
duplicate items not allowed.</li>'; }; // create an object store on the transaction var objectstore = transaction.objectstore("todolist"); // add our newitem object to the object store var objectstorerequest = objectstore.add(newitem[0]); objectstorerequest.onsuccess = function(event) { // repor...

IDBTransaction.mode - Web APIs
duplicate items not allowed.</li>'; }; // create an object store on the transaction var objectstore = transaction.objectstore("todolist"); // add our newitem object to the object store var objectstorerequest = objectstore.add(newitem[0]); objectstorerequest.onsuccess = function(event) { // repor...

IDBTransaction.objectStore() - Web APIs
duplicate items not allowed.</li>'; }; // create an object store on the transaction var objectstore = transaction.objectstore("todolist"); // add our newitem object to the object store var objectstorerequest = objectstore.add(newitem[0]); objectstorerequest.onsuccess = function(event) { // repor...

IDBTransaction.onabort - Web APIs
, day: 24, month: "december", year: 2013, notified: "no" } ]; // open a read/write db transaction, ready for adding the data var transaction = db.transaction(["todolist"], "readwrite"); // report on the success of opening the transaction transaction.oncomplete = function(event) { note.innerhtml += '<li>transaction completed: database modification finished.</li>'; }; transaction.onerror = function(event) { note.innerhtml += '<li>transaction not opened due to error: ' + transaction.error + '</li>'; }; // create an object store on the transaction var objectstore = transaction.objectstore("todolist"); // add our newitem object to the object store var objectstorerequest = objectstore.add(newitem[0]); objectstorerequest.onsuccess = function(event) { // report t...

IDBTransaction.oncomplete - Web APIs
, day: 24, month: "december", year: 2013, notified: "no" } ]; // open a read/write db transaction, ready for adding the data var transaction = db.transaction(["todolist"], "readwrite"); // report on the success of opening the transaction transaction.oncomplete = function(event) { note.innerhtml += '<li>transaction completed: database modification finished.</li>'; }; transaction.onerror = function(event) { note.innerhtml += '<li>transaction not opened due to error: ' + transaction.error + '</li>'; }; // create an object store on the transaction var objectstore = transaction.objectstore("todolist"); // add our newitem object to the object store var objectstorerequest = objectstore.add(newitem[0]); objectstorerequest.onsuccess = function(event) { // report t...

IDBVersionChangeEvent.newVersion - Web APIs
// this is used a lot later on, for opening transactions and suchlike. db = dbopenrequest.result; }; specifications specification ...

IDBVersionChangeEvent - Web APIs
this is used a lot later on, for opening transactions and suchlike. db = dbopenrequest.result; }; specifications specification statu...

Basic concepts - Web APIs
ishes, and the type of event you get lets you know if the operation succeeded or failed. this sounds a little complicated at first, but there are sanity measures baked in. it's not that different from the way that xmlhttprequest works. indexeddb uses a lot of requests. requests are objects that receive the success or failure dom events that were mentioned previously. they have onsuccess and onerror properties, and you can call addeventlistener() and removeeventlistener() on them. they also have readystate, result, and errorcode properties that tell you the status of the request. the result property is particularly magical, as it can be many different things, depending on how the request was generated (for example, an idbcursor instance, or the key for a value that you just inserted into the...

Checking when a deadline is due - Web APIs
duplicate items not allowed.</li>'; }; // create an object store on the transaction var objectstore = transaction.objectstore("todolist"); // add our newitem object to the object store var request = objectstore.add(newitem[0]); in this section we create an object called newitem that store...

LockedFile - Web APIs
.active read only a flag indicating if the file can be accessed (true) or not (false). lockedfile.location the position of the reading/writing pointer within the file. events handler lockedfile.oncomplete the complete event is triggered each time a read or write operation is successful. lockedfile.onabort the abort event is triggered each time the abort() method is called. lockedfile.onerror the error event is triggered each time something goes wrong. methods lockedfile.getmetadata() allows to retrieve the file metadata (size and date of the last modification). returns a filerequest. lockedfile.readasarraybuffer() allows to retrieve a part of the content of the file as an arraybuffer. returns a filerequest object. lockedfile.readastext() allows to retrieve a part of the co...

MediaError.code - Web APIs
_supported 4 the associated resource or media provider object (such as a mediastream) has been found to be unsuitable. example this example creates a <video> element, establishes an error handler for it, and then sets the element's src attribute to the video resource to present in the element. the error handler simply outputs a message var obj = document.createelement('video'); obj.onerror = function() {console.log("error with media: " + obj.error.code);} obj.src="https://example.com/blahblah.mp4"; specifications specification status comment html living standardthe definition of 'mediaerror.code' in that specification. living standard initial definition ...

MediaError.message - Web APIs
arts of the code are displayed; you can see the complete source code here. the example creates an <audio> element and lets the user assign either a valid music file to it, or a link to a file which doesn't exist. this lets us see the behavior of the error event handler, which is received by an event handler we add to the <audio> element itself. ...

MediaRecorder.start() - Web APIs
tion is recorded into a single blob unless the requestdata() method is called to obtain the blob and trigger the creation of a new blob into which the media continues to be recorded. return value undefined. exceptions errors that can be detected immediately are thrown as dom exceptions. all other errors are reported through error events sent to the mediarecorder object. you can implement the onerror event handler to respond to these errors. invalidmodificationerror the number of tracks on the stream being recorded has changed. you can't add or remove tracks while recording media. invalidstateerror the mediarecorder is not in the inactive state; you can't start recording media if it's already being recorded. see the state property. notsupportederror the media stream you're attempting ...

MediaRecorderErrorEvent() - Web APIs
syntax var errorevent = new mediarecordererrorevent(errorinfo) parameters errorinfo an object describing the error object to be created. ...

MediaSource.endOfStream() - Web APIs
when the end of the stream is reached. the possible values are: network: terminates playback and signals that a network error has occured. this can be used create a custom error handler related to media streams. for example, you might have a function that handles media chunk requests, separate from other network requests. when you make an xmlhttprequest call for a media chunk, and onabort or onerror triggers, you might want to call endofstream('network'), display a descriptive message in the ui, and maybe retry the network request immediately or wait until the network is back up (via some kind of polling.) decode: terminates playback and signals that a decoding error has occured. this can be used to indicate that a parsing error has occured while fetching media data; maybe the data is corr...

MediaStream Recording API - Web APIs
he source media stops playing. you can stop recording at any time by calling mediarecorder.stop(). note: individual blobs containing slices of the recorded media will not necessarily be individually playable. the media needs to be reassembled before playback. if anything goes wrong during recording, an error event is sent to the mediarecorder. you can listen for error events by setting up a onerror event handler. example here, we use an html canvas as source of the mediastream, and stop recording after 9 seconds. var canvas = document.queryselector("canvas"); // optional frames per second argument. var stream = canvas.capturestream(25); var recordedchunks = []; console.log(stream); var options = { mimetype: "video/webm; codecs=vp9" }; mediarecorder = new mediarecorder(stream, options)...

NDEFReader - Web APIs
ndefreader.ndefreader() returns an ndefreader with configuration specified in the parameters or default ones if no parameters are specified. properties in addition to the properties listed below, ndefreader inherits properties from its parent interface, eventtarget. ndefreader.onreading an event handler for reading event, that notifies about availability of a new reading. ndefreader.onerror an event handler for error event which is called to notify that an error occured during reading. methods the ndefreader interface inherits the methods of eventtarget, its parent interface. ndefreader.scan() called to activate the reader (after ensuring hardware and ua compatibility and obtaining permission from the user) or get an error explaining why feature is not available. speci...

Notification - Web APIs
t parameter of the constructor. notification.vibrate read only specifies a vibration pattern for devices with vibration hardware to emit. event handlers notification.onclick a handler for the click event. it is triggered each time the user clicks on the notification. notification.onclose a handler for the close event. it is triggered when the user closes the notification. notification.onerror a handler for the error event. it is triggered each time the notification encounters an error. notification.onshow a handler for the show event. it is triggered when the notification is displayed. methods static methods these methods are available only on the notification object itself. notification.requestpermission() requests permission from the user to display notifications. insta...

Using the Notifications API - Web APIs
fication instance: click triggered when the user clicks on the notification. close triggered once the notification is closed. error triggered if something goes wrong with the notification; this is usually because the notification couldn't be displayed for some reason. show triggered when the notification is displayed to the user. these events can be tracked using the onclick, onclose, onerror, and onshow handlers. because notification also inherits from eventtarget, it's possible to use the addeventlistener() method on it. replacing existing notifications it is usually undesirable for a user to receive a lot of notifications in a short space of time — for example, what if a messenger application notified a user for each incoming message, and they were being sent a lot? to avoid sp...

PaintWorklet.registerPaint - Web APIs
intworklet interface registers a class programmatically generate an image where a css property expects a file. syntax registerpaint(name, class); parameters name the name of the worklet class to register. class a reference to the class that implements the worklet. return value undefined exceptions typeerror thrown when one of the arguments is invalid or missing. invalidmodificationerror thrown when the a worklet already exists with the specified name. examples the following shows registering an example worklet module. this should be in a separate js file. note that registerpaint() is called without a reference to paintworklet. the file itself is loaded through css.paintworklet.addmodule() (documented here on the parent class of paintworklet, at worklet.addmodule(). /* check...

PaymentResponse.retry() - Web APIs
the paymentresponse interface's retry() method makes it possible to ask the user to retry a payment after an error occurs during processing. this lets your app gracefully deal with situations such as invalid shipping addresses or declined credit cards. syntax retrypromise = paymentrequest.retry(errorfields); parameters errorfields a paymentvalidationerrors object, with the following properties: error optional a general description of a payment error from which the user may attempt to recover by retrying the payment, possibly after correcting mistakes in the payment information. error can be provided all by itself to provide only a generic error message, or in concert with the other properties to serve as an overview while other properties' values gude the user to errors in speci...

Payment Request API - Web APIs
bject providing redacted address information that is provided as the methoddetails on the paymentmethodchange event sent to the paymentrequest when the user changes payment information. basiccarderrors an object providing any error messages associated with the fields in the basiccardresponse object that are not valid. this is used as the value of the paymentmethod property on the paymentvalidationerrors object sent to the paymentrequest when an error occurs. basiccardrequest defines an object structure for containing payment request details such as card type. basiccardresponse defines an object structure for payment response details such as the number/expiry date of the card used to make the payment, and the billing address. specifications specification status comment ...

PushManager.register() - Web APIs
cess or failure of the method call. if the method call is successful, the request's result will be a string, which is the endpoint url. note: if you do not need the url any more, please use pushmanager.unregister() to clean up after yourself. example var req = navigator.push.register(); req.onsuccess = function(e) { var endpoint = req.result; debug("new endpoint: " + endpoint ); } req.onerror = function(e) { debug("error getting a new endpoint: " + json.stringify(e)); } specification specification status comment push api working draft defines the pushmanager interface. ...

PushManager.unregister() - Web APIs
istration those objects are anonymous javascript objects with the following properties: pushendpoint a string representing the url of the unregistered endpoint. version undefined when unregister.onsuccess is called. example var req = navigator.push.unregister(pushendpoint); req.onsuccess = function(e) { var endpoint = req.result; debug("unregistered endpoint: " + endpoint ); } req.onerror = function(e) { debug("error unregistering the endpoint: " + json.stringify(e)); } specification specification status comment push api working draft defines the pushmanager interface. ...

RTCIceCandidate.address - Web APIs
address in the options object, but the address is automatically extracted from the candidate a-line, if it's formatted properly. syntax var address = rtcicecandidate.address; value a domstring providing the ip address from which the candidate comes. note: if port is null — and port is supported by the user agent — passing the candidate to addicecandidate() will fail, throwing an operationerror exception. security notes it's important to note here that although webrtc does not require the two peers on an rtcpeerconnection to know one another's true ip addresses, the address property on rtcicecandidate can expose more information about the source of the remote peer than the user expects. the ip address can be used to derive information about the remote device's location, network topol...

RTCIceCandidate.foundation - Web APIs
n be used to correlate candidates that are present on multiple rtcicetransport objects syntax var foundation = rtcicecandidate.foundation; value a domstring which uniquely identifies the candidate across all rtcicetransports on which it is available. note: if port is null — and port is supported by the user agent — passing the candidate to addicecandidate() will fail, throwing an operationerror exception. usage notes consider this sdp attribute line (a-line) which describes an ice candidate: a=candidate:4234997325 1 udp 2043278322 192.168.0.56 44323 typ host the field "4234997325" is the foundation. example this code snippet uses the foundation of two candidates to determine if they're actually the same candidate. if (candidate1.foundation == candidate2.foundation) { /* the t...

RTCIceCandidate.port - Web APIs
x var port = rtcicecandidate.port; value a 16-bit number indicating the port number on the device at the address indicated by ip at which the candidate's peer can be reached. port is initialized to null if it is not specified in the candidate, or if the candidate string can't be parsed propertly. note: if port is null, passing the candidate to addicecandidate() will fail, throwing an operationerror exception. this applies only if the candidate implements port. usage notes consider this sdp attribute line (a-line) which describes an ice candidate: a=candidate:4234997325 1 udp 2043278322 192.168.0.56 44323 typ host the port number is found in the sixth field, which is "44323". in this case, the value of port will be 44323. example this code snippet fetches the ip address and port numbe...

RTCIceCandidate.priority - Web APIs
alue indicating the priority of the candidate according to the remote peer. the larger this value is, the more preferable the remote peer considers this candidate to be. priority is initialized to null if it is not specified in the candidate, or if the candidate string can't be parsed propertly. note: if priority is null, passing the candidate to addicecandidate() will fail, throwing an operationerror exception. this applies only if the candidate implements the priority property. usage notes consider this sdp attribute line (a-line) which describes an ice candidate: a=candidate:4234997325 1 udp 2043278322 192.168.0.56 44323 typ host the priority is the number after the protocol, so it's the fourth field in the candidate string. in this example, the priority is 2043278322. example this c...

RTCIceCandidate.protocol - Web APIs
itional information about the kind of tcp candidate represented by the object. udp the candidate will use the udp transport protocol for its data. this is the preferred protocol for media interactions because of its better performance profile. note: if protocol is null — and protocol is supported by the user agent — passing the candidate to addicecandidate() will fail, throwing an operationerror exception. usage notes here's an example candidate a-line from an ice transaction: a=candidate:4234997325 1 udp 2043278322 192.168.0.56 44323 typ host the third field, "udp", is the protocol type, indicating that the candidate would use the udp transport protocol. example this code snippet examines the value of protocol to decide if it should look at the value of tcptype to see if it's a s...

RTCIceCandidate.type - Web APIs
y the stun server to represent the candidate's peer anonymously. relay the candidate is a relay candidate, obtained from a turn server. the relay candidate's ip address is an address the turn server uses to forward the media between the two peers. if type is null, that information was missing from the candidate's a-line, which will cause rtcpeerconnection.addicecandidate() to throw an operationerror exception. example in this example, the candidate's type is used to present a modified user interface for host candidates (those where the ip refers directly to the remote peer, rather than an intermediary). if (candidate.type == "host") { showhostcontrols(); } else { hidehostcontrols(); } specifications specification status comment webrtc 1.0: real-time communic...

RTCIdentityErrorEvent.idp - Web APIs
ovider (idp) generating the error response event. firefox implements the interface of this property under the following name: rtcpeerconnectionidentityerrorevent. ...

RTCIdentityErrorEvent.loginUrl - Web APIs
ty provider (idp). firefox implements the interface of this property under the following name: rtcpeerconnectionidentityerrorevent. it is likely that it will correct this name when it will unprefix rtcpeerconnection, once spec and implementation will have been stabilized. ...

RTCIdentityErrorEvent.protocol - Web APIs
a domstring describing the idp protocol in use. firefox implements the interface of this property under the following name: rtcpeerconnectionidentityerrorevent. ...

RTCPeerConnection.addIceCandidate() - Web APIs
o add the ice candidate, the promise returned by this method is rejected, returning one of the errors below as the name attribute in the specified domexception object passed to the rejection handler. typeerror the specified candidate's sdpmid and sdpmlineindex are both null. invalidstateerror the rtcpeerconnection currently has no remote peer established (remotedescription is null). operationerror this can happen for a number of reasons: the value specified for sdpmid is non-null and doesn't match the media description id of any media description included within the remotedescription. the specified value of sdpmlineindex is greater than or equal to the number of media descriptions included in the remote description. the specified ufrag doesn't match the ufrag field in any of the r...

RTCPeerConnection.createDataChannel() - Web APIs
5 bytes (bytes, rather than characters). the id is 65535. while this is a valid unsigned 16-bit value, it's not a permitted value for id. syntaxerror values were specified for both the maxpacketlifetime and maxretransmits options. you may only specify a non-null value for one of these. resourceinuse an id was specified, but another rtcdatachannel is already using the same value. operationerror either the specified id is already in use or, if no id was specified, the webrtc layer was unable to automatically generate an id because all ids are in use. examples this example shows how to create a data channel and set up handlers for the open and message events to send and receive messages on it (for brievity, the example assumes onnegotiationneeded is set up). // offerer side var pc =...

RTCPeerConnection.getIdentityAssertion() - Web APIs
it is not expected for the application dealing with the rtcpeerconnection: this is automatically done; an explicit call only allows to anticipate the need. syntax pc.getidentityassertion(); there is neither parameter nor return value for this method. ...

RTCPeerConnection.setConfiguration() - Web APIs
changes are not additive; instead, the new values completely replace the existing ones. exceptions invalidaccesserror one or more of the urls specified in configuration.iceservers is a turn server, but complete login information is not provided (that is, either the rtciceserver.username or rtciceserver.credentials is missing). this prevents successful login to the server. invalidmodificationerror the configuration includes changed identity information, but the connection already has identity information specified. this happens if configuration.peeridentity or configuration.certificates is set and their values differ from the current configuration. invalidstateerror the rtcpeerconnection is closed. syntaxerror one or more of the urls provided in the configuration.iceservers list is in...

RTCRtpSender.replaceTrack() - Web APIs
is not allowed (see things that require negotiation). if newtrack was omitted or was null, replacetrack() simply stops the sender. no negotiation is required in this case. when the promise is fulfilled, the fulfillment handler receives a value of undefined. exceptions if the returned promise is rejected, one of the following exceptions is provided to the rejection handler: invalidmodificationerror replacing the rtcrtpsender's current track with the new one would require negotiation. invalidstateerror the track on which this method was called is stopped rather than running. typeerror the new track's kind doesn't match the original track. usage notes things that trigger negotiation not all track replacements require renegotiation. in fact, even changes that seem huge can be done wit...

SVGElement: error event - Web APIs
the error event is fired when an svg element does not load properly or when an error occurs during script execution. this basically implements the standard error dom event. bubbles yes cancelable no interface svgevent event handler property onerror examples svgelem.addeventlistener('error', () => { console.log('svg not loaded properly.'); }) specifications specification status comment scalable vector graphics (svg) 2the definition of 'error' in that specification. candidate recommendation initial definition ...

SVGElement - Web APIs
assigning an event listener to the equivalent on... handler property defined on globaleventhandlers or windoweventhandlers. abort fired when page loading is stopped before an svg element has been allowed to load completely. also available via the onabort property. error fired when an svg element does not load properly or when an error occurs during script execution. also available via the onerror property. load fires on an svgelement when it is loaded in the browser. also available via the onload property. resize fired when an svg document is being resized. also available via the onresize property. scroll fired when an svg document view is being shifted along the x and/or y axes. also available via the onscroll property. unload fired when the dom implementation removes an svg d...

Sensor - Web APIs
ambientlightsensor gyroscope linearaccelerationsensor magnetometer orientationsensor properties sensor.activated read only returns a boolean indicating whether the sensor is active. sensor.hasreading read only returns a boolean indicating whether the sensor has a reading. sensor.timestamp read only returns the time stamp of the latest sensor reading. event handlers sensor.onerror called when an error occurs on one of the child interfaces of the sensor interface. sensor.onreading called when a reading is taken on one of the child interfaces of the sensor interface. sensor.onactivate called when one of the sensor interface's becomes active. methods sensor.start() activates one of the sensors based on sensor. sensor.stop() deactivates one of the sensors based on...

Using server-sent events - Web APIs
enerated. at random intervals, a simple message (with no event type) is sent. note: you can find a full example that uses the code shown in this article on github — see simple sse demo using php. error handling when problems occur (such as a network timeout or issues pertaining to access control), an error event is generated. you can take action on this programmatically by implementing the onerror callback on the eventsource object: evtsource.onerror = function(err) { console.error("eventsource failed:", err); }; closing event streams by default, if the connection between the client and server closes, the connection is restarted. the connection is terminated with the .close() method. evtsource.close(); event stream format the event stream is a simple stream of text data which must...

ServiceWorkerContainer - Web APIs
r. once that condition is met, it resolves with the serviceworkerregistration. events controllerchange occurs when the document's associated serviceworkerregistration acquires a new active worker. also available via the serviceworkercontainer.oncontrollerchange property. error fired whenever an error occurs in the associated service workers. also available via the serviceworkercontainer.onerror property. message occurs when incoming messages are received by the serviceworkercontainer object (e.g. via a messageport.postmessage() call.) also available via the serviceworkercontainer.onmessage property. methods serviceworkercontainer.register() creates or updates a serviceworkerregistration for the given scripturl. serviceworkercontainer.getregistration() gets a serviceworkerreg...

Using Service Workers - Web APIs
...

SharedWorker.port - Web APIs
living standard ...

SharedWorker - Web APIs
ote: if sharedworker can be accessed from several browsing contexts, all those browsing contexts must share the exact same origin (same protocol, host and port). constructors sharedworker() creates a shared web worker that executes the script at the specified url. properties inherits properties from its parent, eventtarget, and implements properties from abstractworker. abstractworker.onerror is an eventlistener that is called whenever an errorevent of type error bubbles through the worker. sharedworker.port read only returns a messageport object used to communicate with and control the shared worker. methods inherits methods from its parent, eventtarget, and implements methods from abstractworker. example in our basic shared worker example (run shared worker), we have two...

SourceBuffer - Web APIs
m(), or sourcebuffer.remove() operation is currently in progress. sourcebuffer.videotracks read only a list of the video tracks currently contained inside the sourcebuffer. event handlers sourcebuffer.onabort fired whenever sourcebuffer.appendbuffer() or sourcebuffer.appendstream() is ended by a call to sourcebuffer.abort(). sourcebuffer.updating changes from true to false. sourcebuffer.onerror fired whenever an error occurs during sourcebuffer.appendbuffer() or sourcebuffer.appendstream(). sourcebuffer.updating changes from true to false. sourcebuffer.onupdate fired whenever sourcebuffer.appendbuffer() method or the sourcebuffer.remove() completes. sourcebuffer.updating changes from true to false. this event is fired before onupdateend. sourcebuffer.onupdateend fired whenever sour...

SpeechRecognition - Web APIs
fired when the user agent has started to capture audio. also available via the onaudiostart property. audioend fired when the user agent has finished capturing audio. also available via the onaudioend property. end fired when the speech recognition service has disconnected. also available via the onend property. error fired when a speech recognition error occurs. also available via the onerror property. nomatch fired when the speech recognition service returns a final result with no significant recognition. this may involve some degree of recognition, which doesn't meet or exceed the confidence threshold. also available via the onnomatch property. result fired when the speech recognition service returns a result — a word or phrase has been positively recognized and this has been...

SpeechSynthesisErrorEvent.error - Web APIs
etvoices(); ... inputform.onsubmit = function(event) { event.preventdefault(); var utterthis = new speechsynthesisutterance(inputtxt.value); var selectedoption = voiceselect.selectedoptions[0].getattribute('data-name'); for(i = 0; i < voices.length ; i++) { if(voices[i].name === selectedoption) { utterthis.voice = voices[i]; } } synth.speak(utterthis); utterthis.onerror = function(event) { console.error('an error has occurred with the speech synthesis: ' + event.error); } inputtxt.blur(); } specifications specification status comment web speech apithe definition of 'error' in that specification. draft ...

SpeechSynthesisErrorEvent - Web APIs
etvoices(); ... inputform.onsubmit = function(event) { event.preventdefault(); var utterthis = new speechsynthesisutterance(inputtxt.value); var selectedoption = voiceselect.selectedoptions[0].getattribute('data-name'); for(i = 0; i < voices.length ; i++) { if(voices[i].name === selectedoption) { utterthis.voice = voices[i]; } } synth.speak(utterthis); utterthis.onerror = function(event) { console.log('an error has occurred with the speech synthesis: ' + event.error); } inputtxt.blur(); } specifications specification status comment web speech apithe definition of 'speechsynthesiserrorevent' in that specification. draft ...

SpeechSynthesisUtterance - Web APIs
listener to the oneventname property of this interface. boundary fired when the spoken utterance reaches a word or sentence boundary. also available via the onboundary property. end fired when the utterance has finished being spoken. also available via the onend property. error fired when an error occurs that prevents the utterance from being succesfully spoken. also available via the onerror property mark fired when the spoken utterance reaches a named ssml "mark" tag. also available via the onmark property. pause fired when the utterance is paused part way through. also available via the onpause property. resume fired when a paused utterance is resumed. also available via the onresume property. start fired when the utterance has begun to be spoken. also available via the...

SubtleCrypto.decrypt() - Web APIs
o known as ciphertext). return value result is a promise that fulfills with an arraybuffer containing the plaintext. exceptions the promise is rejected when the following exceptions are encountered: invalidaccesserror raised when the requested operation is not valid for the provided key (e.g. invalid encryption algorithm, or invalid key for the specified encryption algorithm). operationerror raised when the operation failed for an operation-specific reason (e.g. algorithm parameters of invalid sizes, or there was an error decrypting the ciphertext). supported algorithms the decrypt() method supports the same algorithms as the encrypt() method. examples note: you can try the working examples on github. rsa-oaep this code decrypts ciphertext using rsa-oaep. see the complete c...

SubtleCrypto.encrypt() - Web APIs
s the plaintext). return value result is a promise that fulfills with an arraybuffer containing the "ciphertext". exceptions the promise is rejected when the following exceptions are encountered: invalidaccesserror raised when the requested operation is not valid for the provided key (e.g. invalid encryption algorithm, or invalid key for the specified encryption algorithm). operationerror raised when the operation failed for an operation-specific reason (e.g. algorithm parameters of invalid sizes, or aes-gcm plaintext longer than 2³⁹−256 bytes). supported algorithms the web crypto api provides four algorithms that support the encrypt() and decrypt() operations. one of these algorithms — rsa-oaep — is a public-key cryptosystem. the other three encryption algorithms h...

WebGLContextEvent.statusMessage - Web APIs
the read-only webglcontextevent.statusmessage property contains additional event status information, or is an empty string if no additional information is available. examples the statusmessage property can contain a platform dependent string with details of an event. this can occur, for example, if the webglcontextcreationerror event is fired. var canvas = document.getelementbyid('canvas'); var gl = canvas.getcontext('webgl'); canvas.addeventlistener('webglcontextcreationerror', function(e) { console.log('webgl context creation failed:' + e.statusmessage || 'unknown error'); }, false); specifications specification status comment webgl 1.0the definition of 'webglcontextevent.statusmessage' in that specification. recommendation initial definitio...

WebGL: 2D and 3D graphics for the web - Web APIs
it is based on opengl es 3.0 and new features include: 3d textures, sampler objects, uniform buffer objects, sync objects, query objects, transform feedback objects, promoted extensions that are now core to webgl 2: vertex arr...

A simple RTCDataChannel sample - Web APIs
first, we call rtcpeerconnection.createoffer() method to create an sdp (session description protocol) blob describing the connection we want to make. this method accepts, optionally, an object with constraints to be met for the connection to meet your needs, such as whether the connection should support audio, video, or both. in...

WebRTC API - Web APIs
sters an identity provider (idp). rtcidentityevent represents an identity assertion generated by an identity provider (idp). this is usually for an rtcpeerconnection. the only event sent with this type is identityresult. rtcidentityerrorevent represents an error associated with the identity provider (idp). this is usually for an rtcpeerconnection. two events are sent with this type: idpassertionerror and idpvalidationerror. rtccertificate represents a certificate that an rtcpeerconnection uses to authenticate. telephony these interfaces and events are related to interactivity with public-switched telephone networks (ptsns). they're primarily used to send tone dialing sounds—or packets representing those tones—across the network to the remote peer. interfaces rtcdtmfsender manage...

WebSocket: error event - Web APIs
the error event is fired when a connection with a websocket has been closed due to an error (some data couldn't be sent for example). bubbles no cancelable no interface event event handler property onerror examples // create websocket connection const socket = new websocket('ws://localhost:8080'); // listen for possible errors socket.addeventlistener('error', function (event) { console.log('websocket error: ', event); }); specifications specification status html living standardthe definition of 'websocket error' in that specification. living standard ...

Writing WebSocket client applications - Web APIs
destination doesn't allow access. this may happen if you attempt to use an insecure connection (most user agents now require a secure link for all websocket connections unless they're on the same device or possibly on the same network). connection errors if an error occurs while attempting to connect, first a simple event with the name error is sent to the websocket object (thereby invoking its onerror handler), and then the closeevent is sent to the websocket object (thereby invoking its onclose handler) to indicate the reason for the connection's closing. the browser may also output to its console a more descriptive error message as well as a closing code as defined in rfc 6455, section 7.4 through the closeevent. examples this simple example creates a new websocket, connecting to the serv...

Writing a WebSocket server in C# - Web APIs
socket(wsuri); button.addeventlistener("click", onclickbutton); websocket.onopen = function (e) { writetoscreen("connected"); dosend("websocket rocks"); }; websocket.onclose = function (e) { writetoscreen("disconnected"); }; websocket.onmessage = function (e) { writetoscreen("<span>response: " + e.data + "</span>"); }; websocket.onerror = function (e) { writetoscreen("<span class=error>error:</span> " + e.data); }; function dosend(message) { writetoscreen("sent: " + message); websocket.send(message); } function writetoscreen(message) { output.insertadjacenthtml("afterbegin", "<p>" + message + "</p>"); } function onclickbutton() { var text = textarea.value; ...

Web Speech API - Web APIs
e details on using these features, see using the web speech api. web speech api interfaces speech recognition speechrecognition the controller interface for the recognition service; this also handles the speechrecognitionevent sent from the recognition service. speechrecognitionalternative represents a single word that has been recognised by the speech recognition service. speechrecognitionerror represents error messages from the recognition service. speechrecognitionevent the event object for the result and nomatch events, and contains all the data associated with an interim or final speech recognition result. speechgrammar the words or patterns of words that we want the recognition service to recognize. speechgrammarlist represents a list of speechgrammar objects. speechrecogni...

Window: error event - Web APIs
the error event is fired on a window object when a resource failed to load or couldn't be used — for example if a script has an execution error. bubbles no cancelable no interface event or uievent event handler property onerror the event object is a uievent instance if it was generated from a user interface element, or an event instance otherwise. examples live example html <div class="controls"> <button id="script-error" type="button">generate script error</button> <img class="bad-img" /> </div> <div class="event-log"> <label>event log:</label> <textarea readonly class="event-log-contents" rows="8" cols="30"></textarea> </div> css body { display: grid; grid-template-areas: "control log"; } .controls { grid-area: c...

Worker - Web APIs
ions.) in firefox extensions, if you want to use workers with access to js-ctypes, use chromeworker object instead. constructors worker() creates a dedicated web worker that executes the script at the specified url. this also works for blob urls. properties inherits properties from its parent, eventtarget, and implements properties from abstractworker. event handlers abstractworker.onerror an eventlistener called whenever an errorevent of type error bubbles through to the worker. this is inherited from abstractworker. worker.onmessage an eventlistener called whenever a messageevent of type message bubbles through the worker — i.e. when a message is sent to the parent document from the worker via dedicatedworkerglobalscope.postmessage. the message is stored in the event's data ...

WorkerGlobalScope - Web APIs
indoworworkerglobalscope.issecurecontext read only returns a boolean indicating whether the current context is secure (true) or not (false). windoworworkerglobalscope.origin read only returns the global object's origin, serialized as a string. (this does not yet appear to be implemented in any browser.) events error fired when an error occured. also available via the workerglobalscope.onerror property. offline fired when the browser has lost access to the network and the value of navigator.online switched to false. also available via the workerglobalscope.onoffline property. online fired when the browser has gained access to the network and the value of navigator.online switched to true. also available via the workerglobalscope.ononline property. languagechange fired at the gl...

HTML in XMLHttpRequest - Web APIs
{ if (!window.xmlhttprequest) { window.settimeout(function() { callback(false); }, 0); return; } var done = false; var xhr = new window.xmlhttprequest(); xhr.onreadystatechange = function() { if (this.readystate == 4 && !done) { done = true; callback(!!(this.responsexml && this.responsexml.title && this.responsexml.title == "&&<")); } } xhr.onabort = xhr.onerror = function() { if (!done) { done = true; callback(false); } } try { xhr.open("get", "detect.html"); xhr.responsetype = "document"; xhr.send(); } catch (e) { window.settimeout(function() { if (!done) { done = true; callback(false); } }, 0); } } the argument callback is a function that will be called asynchronously with t...

How to check the security state of an XMLHTTPRequest over SSL - Web APIs
ateerror'; break; case 4: // ssl_error_bad_certificate, ssl(4) errname = 'securitybadcertificateerror'; break; case 8: // ssl_error_unsupported_certificate_type, ssl(8) errname = 'securityunsupportedcertificatetypeerror'; break; case 9: // ssl_error_unsupported_version, ssl(9) errname = 'securityunsupportedtlsversionerror'; break; case 12: // ssl_error_bad_cert_domain, ssl(12) errname = 'securitycertificatedomainmismatcherror'; break; default: errname = 'securityerror'; break; } } } else { errtype = 'network'; switch (status) { // connect to host:port failed case 0x804b000c: // ns_error_connection_refused, network(13)...

XMLHttpRequest.upload - Web APIs
its process. the following events can be triggered on an upload object and used to monitor the upload: event event listener description loadstart onloadstart the upload has begun. progress onprogress periodically delivered to indicate the amount of progress made so far. abort onabort the upload operation was aborted. error onerror the upload failed due to an error. load onload the upload completed successfully. timeout ontimeout the upload timed out because a reply did not arrive within the time interval specified by the xmlhttprequest.timeout. loadend onloadend the upload finished. this event does not differentiate between success or failure, and is sent at the end of the up...

XMLHttpRequestEventTarget - Web APIs
mily="consolas,monaco,andale mono,monospace" fill="#4d4e53" text-anchor="middle" alignment-baseline="middle">xmlhttprequesteventtarget</text></a></svg></div> a:hover text { fill: #0095dd; pointer-events: all;} properties xmlhttprequesteventtarget.onabort contains the function to call when a request is aborted and the abort event is received by this object. xmlhttprequesteventtarget.onerror contains the function to call when a request encounters an error and the error event is received by this object. xmlhttprequesteventtarget.onload contains the function to call when an http request returns after successfully fetching content and the load event is received by this object. xmlhttprequesteventtarget.onloadstart contains the function that gets called when the http request first b...

XRWebGLLayer() - Web APIs
configuration. exceptions invalidstateerror the new xrwebgllayer could not be created due to one of a number of possible state errors: the xrsession specified by session has already been stopped. the specified webgl context, context, has been lost for any reason, such as a gpu switch or reset. the specified session is immersive but the context is not webxr compatible. operationerror the resources (including memory buffers) needed for the layer to operate could not be allocated. specifications specification status comment webxr device apithe definition of 'xrwebgllayer()' in that specification. working draft initial definition. ...

DOM onevent handlers - Developer guides
'anchoronclick(event)'); log(`changed the property to: <code> ${el.onclick.tostring()} </code>`); log(`now even the html attribute has changed: <code> ${el.getattribute("onclick")} </code><br>`); result for historical reasons, some attributes/properties on the <body> and <frameset> elements instead set event handlers on their parent window object. (the html specification names these: onblur, onerror, onfocus, onload, and onscroll.) event handler's parameters, this binding, and the return value when the event handler is specified as an html attribute, the specified code is wrapped into a function with the following parameters: event — for all event handlers except onerror. event, source, lineno, colno, and error for the onerror event handler. note that the event parameter actually con...

Parsing and serializing XML - Developer guides
if the document is html, the code shown above will return a document. if the document is xml, the resulting object is actually a xmldocument. the two types are essen...

<body>: The Document Body element - HTML: Hypertext Markup Language
ks. this method is non-conforming, use css color property in conjunction with the :link pseudo-class instead. onafterprint function to call after the user has printed the document. onbeforeprint function to call when the user requests printing of the document. onbeforeunload function to call when the document is about to be unloaded. onblur function to call when the document loses focus. onerror function to call when the document fails to load properly. onfocus function to call when the document receives focus. onhashchange function to call when the fragment identifier part (starting with the hash ('#') character) of the document's current address has changed. onlanguagechange function to call when the preferred languages changed. onload function to call when the document has ...

<img>: The Image Embed element - HTML: Hypertext Markup Language
image/webp .webp chrome, edge, firefox, opera the abbreviation for each format links to a longer description of the format, its capabilities, and detailed browser compatibility information; including which versions introduced support and specific special features that may have been introduced later. image loading errors if an error occurs while loading or rendering an image, and an onerror event handler has been set on the error event, that event handler will get called. this can happen in a number of situations, including: the src attribute is empty ("") or null. the src url is the same as the url of the page the user is currently on. the image is corrupted in some way that prevents it from being loaded. the image's metadata is corrupted in such a way that it's impossible to...

<link>: The External Resource Link element - HTML: Hypertext Markup Language
preload examples you can find a number of <link rel="preload"...

<script>: The Script element - HTML: Hypertext Markup Language
ntinuing to parse. defer has a similar effect in this case. this is a boolean attribute: the presence of a boolean attribute on an element represents the true value, and the absence of the attribute represents the false value. see browser compatibility for notes on browser support. see also async scripts for asm.js. crossorigin normal script elements pass minimal information to the window.onerror for scripts which do not pass the standard cors checks. to allow error logging for sites which use a separate domain for static media, use this attribute. see cors settings attributes for a more descriptive explanation of its valid arguments. defer this boolean attribute is set to indicate to a browser that the script is meant to be executed after the document has been parsed, but before firi...

Global attributes - HTML: Hypertext Markup Language
ty purposes. the multiple aria-* attributes, used for improving accessibility. ...

Feature-Policy: geolocation - HTTP
by default, the geolocation api can be used within top-level documents and their same-origin child frames. this directive allows or prevents cross-origin frames from accessing geolocation. ...

Feature-Policy - HTTP
rols whether the current document is allowed to use element.requestfullscreen(). when this policy is disabled, the returned promise rejects with a typeerror. geolocation controls whether the current document is allowed to use the geolocation interface. when this policy is disabled, calls to getcurrentposition() and watchposition() will cause those functions' callbacks to be invoked with a positionerror code of permission_denied. gyroscope controls whether the current document is allowed to gather information about the orientation of the device through the gyroscope interface. layout-animations controls whether the current document is allowed to show layout animations. legacy-image-formats controls whether the current document is allowed to display images in legacy formats. magnetom...

Index - HTTP
ypeerror. 68 feature-policy: geolocation feature policy, feature-policy, geolocation, http, header the http feature-policy header geolocation directive controls whether the current document is allowed to use the geolocation interface. when this policy is enabled, calls to getcurrentposition() and watchposition() will cause those functions' callbacks to be invoked with a positionerror code of permission_denied. 69 feature-policy: microphone feature policy, feature-policy, http, header, microphone the http feature-policy header microphone directive controls whether the current document is allowed to use audio input devices. when this policy is enabled, the promise returned by mediadevices.getusermedia() will reject with a notallowederror. 70 feat...

HTTP Index - HTTP
peerror. 132 feature-policy: geolocation feature policy, feature-policy, geolocation, http, header the http feature-policy header geolocation directive controls whether the current document is allowed to use the geolocation interface. when this policy is enabled, calls to getcurrentposition() and watchposition() will cause those functions' callbacks to be invoked with a positionerror code of permission_denied. 133 feature-policy: gyroscope the http feature-policy header gyroscope directive controls whether the current document is allowed to gather information about the orientation of the device through the gyroscope interface. 134 feature-policy: layout-animations directive, feature-policy, http, reference, layout-animations the http...

Promise() constructor - JavaScript
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requiredFeatures - SVG: Scalable Vector Graphics
p://www.w3.org/tr/svg11/feature#basicfilter the browser supports the <filter>, <feblend>, <fecolormatrix>, <fecomponenttransfer>, <fecomposite>, <feflood>, <fegaussianblur>, <feimage>, <femerge>, <femergenode>, <feoffset>, <fetile>, <fefuncr>, <fefuncg>, <fefuncb> and <fefunca> elements http://www.w3.org/tr/svg11/feature#documenteventsattribute the browser supports the onunload, onabort, onerror, onresize, onscroll and onzoom attributes http://www.w3.org/tr/svg11/feature#graphicaleventsattribute the browser supports the onfocusin, onfocusout, onactivate, onclick, onmousedown, onmouseup, onmouseover, onmousemove, onmouseout and onload attributes http://www.w3.org/tr/svg11/feature#animationeventsattribute the browser supports the onbegin, onend, onrepeat and onload attributes ...

SVG Attribute reference - SVG: Scalable Vector Graphics
butetype, attributename animation timing attributes begin, dur, end, min, max, restart, repeatcount, repeatdur, fill animation value attributes calcmode, values, keytimes, keysplines, from, to, by, autoreverse, accelerate, decelerate animation addition attributes additive, accumulate event attributes animation event attributes onbegin, onend, onrepeat document event attributes onabort, onerror, onresize, onscroll, onunload global event attributes oncancel, oncanplay, oncanplaythrough, onchange, onclick, onclose, oncuechange, ondblclick, ondrag, ondragend, ondragenter, ondragexit, ondragleave, ondragover, ondragstart, ondrop, ondurationchange, onemptied, onended, onerror, onfocus, oninput, oninvalid, onkeydown, onkeypress, onkeyup, onload, onloadeddata, onloadedmetadata, onloadstart, ...