AudioTrackList

The AudioTrackList interface is used to represent a list of the audio tracks contained within a given HTML media element, with each track represented by a separate AudioTrack object in the list.

Retrieve an instance of this object with HTMLMediaElement.audioTracks. The individual tracks can be accessed using array syntax.

Properties

This interface also inherits properties from its parent interface, EventTarget.

length Read only
The number of tracks in the list.

Event handlers

onaddtrack
An event handler to be called when the addtrack event is fired, indicating that a new audio track has been added to the media element.
onchange
An event handler to be called when the change event occurs. This occurs when one or more tracks have been enabled or disabled by their enabled flag being changed.
onremovetrack
An event handler to call when the removetrack event is sent, indicating that an audio track has been removed from the media element.

Methods

This interface also inherits methods from its parent interface, EventTarget.

getTrackById()
Returns the AudioTrack found within the AudioTrackList whose id matches the specified string. If no match is found, null is returned.

Events

addtrack
Fired when a new audio track has been added to the media element.
Also available via the onaddtrack property.
change
Fired when a track has been enabled or disabled.
Also available via the onchange property.
removetrack
Fired when a new audio track has been removed from the media element.
Also available via the onremovetrack property.

Usage notes

In addition to being able to obtain direct access to the audio tracks present on a media element, AudioTrackList lets you set event handlers on the addtrack and removetrack events, so that you can detect when tracks are added to or removed from the media element's stream. See onaddtrack and onremovetrack for details and examples.

Examples

Getting a media element's audio track list

To get a media element's AudioTrackList, use its audioTracks property.

var audioTracks = document.querySelector("video").audioTracks;

Monitoring track count changes

In this example, we have an app that displays information about the number of channels available. To keep it up to date, handlers for the addtrack and removetrack events are set up.

audioTracks.onaddtrack = updateTrackCount;
audioTracks.onremovetrack = updateTrackCount;

function updateTrackCount(event) {
  trackCount = audioTracks.length;
  drawTrackCountIndicator(trackCount);
}

Specifications

Specification Status Comment
HTML Living Standard
The definition of 'AudioTrackList' in that specification.
Living Standard  
HTML5
The definition of 'AudioTrackList' in that specification.
Recommendation  

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
AudioTrackListChrome Full support 37
Disabled
Full support 37
Disabled
Disabled From version 37: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled). To change preferences in Chrome, visit chrome://flags.
Edge Full support 79
Disabled
Full support 79
Disabled
Disabled From version 79: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled).
No support 12 — 79
Firefox Full support 33
Disabled
Full support 33
Disabled
Disabled From version 33: this feature is behind the media.track.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.
IE Full support 10Opera Full support 24
Disabled
Full support 24
Disabled
Disabled From version 24: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled).
Safari Full support 6.1WebView Android No support NoChrome Android Full support 37
Disabled
Full support 37
Disabled
Disabled From version 37: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled). To change preferences in Chrome, visit chrome://flags.
Firefox Android Full support 33
Disabled
Full support 33
Disabled
Disabled From version 33: this feature is behind the media.track.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.
Opera Android Full support 24
Disabled
Full support 24
Disabled
Disabled From version 24: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled).
Safari iOS Full support 7Samsung Internet Android No support No
addtrack eventChrome Full support 37
Disabled
Full support 37
Disabled
Disabled From version 37: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled). To change preferences in Chrome, visit chrome://flags.
Edge Full support 79
Disabled
Full support 79
Disabled
Disabled From version 79: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled).
No support 12 — 79
Firefox Full support 33
Disabled
Full support 33
Disabled
Disabled From version 33: this feature is behind the media.track.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.
IE Full support 10Opera Full support 24
Disabled
Full support 24
Disabled
Disabled From version 24: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled).
Safari Full support 6.1WebView Android No support NoChrome Android Full support 37
Disabled
Full support 37
Disabled
Disabled From version 37: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled). To change preferences in Chrome, visit chrome://flags.
Firefox Android Full support 33
Disabled
Full support 33
Disabled
Disabled From version 33: this feature is behind the media.track.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.
Opera Android Full support 24
Disabled
Full support 24
Disabled
Disabled From version 24: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled).
Safari iOS Full support 7Samsung Internet Android No support No
change eventChrome Full support 37
Disabled
Full support 37
Disabled
Disabled From version 37: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled). To change preferences in Chrome, visit chrome://flags.
Edge Full support 79
Disabled
Full support 79
Disabled
Disabled From version 79: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled).
No support 12 — 79
Firefox Full support 33
Disabled
Full support 33
Disabled
Disabled From version 33: this feature is behind the media.track.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.
IE Full support 10Opera Full support 24
Disabled
Full support 24
Disabled
Disabled From version 24: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled).
Safari Full support 6.1WebView Android No support NoChrome Android Full support 37
Disabled
Full support 37
Disabled
Disabled From version 37: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled). To change preferences in Chrome, visit chrome://flags.
Firefox Android Full support 33
Disabled
Full support 33
Disabled
Disabled From version 33: this feature is behind the media.track.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.
Opera Android Full support 24
Disabled
Full support 24
Disabled
Disabled From version 24: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled).
Safari iOS Full support 7Samsung Internet Android No support No
getTrackByIdChrome Full support 37
Disabled
Full support 37
Disabled
Disabled From version 37: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled). To change preferences in Chrome, visit chrome://flags.
Edge Full support 79
Disabled
Full support 79
Disabled
Disabled From version 79: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled).
No support 12 — 79
Firefox Full support 33
Disabled
Full support 33
Disabled
Disabled From version 33: this feature is behind the media.track.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.
IE Full support 10Opera Full support 24
Disabled
Full support 24
Disabled
Disabled From version 24: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled).
Safari Full support 6.1WebView Android No support NoChrome Android Full support 37
Disabled
Full support 37
Disabled
Disabled From version 37: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled). To change preferences in Chrome, visit chrome://flags.
Firefox Android Full support 33
Disabled
Full support 33
Disabled
Disabled From version 33: this feature is behind the media.track.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.
Opera Android Full support 24
Disabled
Full support 24
Disabled
Disabled From version 24: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled).
Safari iOS Full support 7Samsung Internet Android No support No
lengthChrome Full support 37
Disabled
Full support 37
Disabled
Disabled From version 37: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled). To change preferences in Chrome, visit chrome://flags.
Edge Full support 79
Disabled
Full support 79
Disabled
Disabled From version 79: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled).
No support 12 — 79
Firefox Full support 33
Disabled
Full support 33
Disabled
Disabled From version 33: this feature is behind the media.track.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.
IE Full support 10Opera Full support 24
Disabled
Full support 24
Disabled
Disabled From version 24: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled).
Safari Full support 6.1WebView Android No support NoChrome Android Full support 37
Disabled
Full support 37
Disabled
Disabled From version 37: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled). To change preferences in Chrome, visit chrome://flags.
Firefox Android Full support 33
Disabled
Full support 33
Disabled
Disabled From version 33: this feature is behind the media.track.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.
Opera Android Full support 24
Disabled
Full support 24
Disabled
Disabled From version 24: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled).
Safari iOS Full support 7Samsung Internet Android No support No
onaddtrackChrome Full support 37
Disabled
Full support 37
Disabled
Disabled From version 37: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled). To change preferences in Chrome, visit chrome://flags.
Edge Full support 79
Disabled
Full support 79
Disabled
Disabled From version 79: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled).
No support 12 — 79
Firefox Full support 33
Disabled
Full support 33
Disabled
Disabled From version 33: this feature is behind the media.track.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.
IE Full support 10Opera Full support 24
Disabled
Full support 24
Disabled
Disabled From version 24: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled).
Safari Full support 6.1WebView Android No support NoChrome Android Full support 37
Disabled
Full support 37
Disabled
Disabled From version 37: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled). To change preferences in Chrome, visit chrome://flags.
Firefox Android Full support 33
Disabled
Full support 33
Disabled
Disabled From version 33: this feature is behind the media.track.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.
Opera Android Full support 24
Disabled
Full support 24
Disabled
Disabled From version 24: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled).
Safari iOS Full support 7Samsung Internet Android No support No
onchangeChrome Full support 37
Disabled
Full support 37
Disabled
Disabled From version 37: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled). To change preferences in Chrome, visit chrome://flags.
Edge Full support 79
Disabled
Full support 79
Disabled
Disabled From version 79: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled).
No support 12 — 79
Firefox Full support 33
Disabled
Full support 33
Disabled
Disabled From version 33: this feature is behind the media.track.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.
IE Full support 10Opera Full support 24
Disabled
Full support 24
Disabled
Disabled From version 24: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled).
Safari Full support 6.1WebView Android No support NoChrome Android Full support 37
Disabled
Full support 37
Disabled
Disabled From version 37: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled). To change preferences in Chrome, visit chrome://flags.
Firefox Android Full support 33
Disabled
Full support 33
Disabled
Disabled From version 33: this feature is behind the media.track.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.
Opera Android Full support 24
Disabled
Full support 24
Disabled
Disabled From version 24: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled).
Safari iOS Full support 7Samsung Internet Android No support No
onremovetrackChrome Full support 37
Disabled
Full support 37
Disabled
Disabled From version 37: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled). To change preferences in Chrome, visit chrome://flags.
Edge Full support 79
Disabled
Full support 79
Disabled
Disabled From version 79: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled).
No support 12 — 79
Firefox Full support 33
Disabled
Full support 33
Disabled
Disabled From version 33: this feature is behind the media.track.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.
IE Full support 10Opera Full support 24
Disabled
Full support 24
Disabled
Disabled From version 24: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled).
Safari Full support 6.1WebView Android No support NoChrome Android Full support 37
Disabled
Full support 37
Disabled
Disabled From version 37: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled). To change preferences in Chrome, visit chrome://flags.
Firefox Android Full support 33
Disabled
Full support 33
Disabled
Disabled From version 33: this feature is behind the media.track.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.
Opera Android Full support 24
Disabled
Full support 24
Disabled
Disabled From version 24: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled).
Safari iOS Full support 7Samsung Internet Android No support No
removetrack eventChrome Full support 37
Disabled
Full support 37
Disabled
Disabled From version 37: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled). To change preferences in Chrome, visit chrome://flags.
Edge Full support 79
Disabled
Full support 79
Disabled
Disabled From version 79: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled).
No support 12 — 79
Firefox Full support 33
Disabled
Full support 33
Disabled
Disabled From version 33: this feature is behind the media.track.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.
IE Full support 10Opera Full support 24
Disabled
Full support 24
Disabled
Disabled From version 24: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled).
Safari Full support 6.1WebView Android No support NoChrome Android Full support 37
Disabled
Full support 37
Disabled
Disabled From version 37: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled). To change preferences in Chrome, visit chrome://flags.
Firefox Android Full support 33
Disabled
Full support 33
Disabled
Disabled From version 33: this feature is behind the media.track.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.
Opera Android Full support 24
Disabled
Full support 24
Disabled
Disabled From version 24: this feature is behind the enable-experimental-web-platform-features preference (needs to be set to enabled).
Safari iOS Full support 7Samsung Internet Android No support No

Legend

Full support  
Full support
No support  
No support
User must explicitly enable this feature.
User must explicitly enable this feature.