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 theirenabled
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 theAudioTrackList
whoseid
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 theonaddtrack
property. change
- Fired when a track has been enabled or disabled.
Also available via theonchange
property. removetrack
- Fired when a new audio track has been removed from the media element.
Also available via theonremovetrack
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
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
AudioTrackList | Chrome
Full support
45
| Edge
Full support
79
| Firefox
Full support
33
| IE Full support 10 | Opera
Full support
32
| Safari Full support 6.1 | WebView Android Full support 45 | Chrome Android
Full support
45
| Firefox Android
Full support
33
| Opera Android
Full support
32
| Safari iOS Full support 7 | Samsung Internet Android No support No |
addtrack event | Chrome
Full support
45
| Edge
Full support
79
| Firefox
Full support
33
| IE Full support 10 | Opera
Full support
32
| Safari Full support 6.1 | WebView Android Full support 45 | Chrome Android
Full support
45
| Firefox Android
Full support
33
| Opera Android
Full support
32
| Safari iOS Full support 7 | Samsung Internet Android No support No |
change event | Chrome
Full support
45
| Edge
Full support
79
| Firefox
Full support
33
| IE Full support 10 | Opera
Full support
32
| Safari Full support 6.1 | WebView Android Full support 45 | Chrome Android
Full support
45
| Firefox Android
Full support
33
| Opera Android
Full support
32
| Safari iOS Full support 7 | Samsung Internet Android No support No |
getTrackById | Chrome
Full support
45
| Edge
Full support
79
| Firefox
Full support
33
| IE Full support 10 | Opera
Full support
32
| Safari Full support 6.1 | WebView Android Full support 45 | Chrome Android
Full support
45
| Firefox Android
Full support
33
| Opera Android
Full support
32
| Safari iOS Full support 7 | Samsung Internet Android No support No |
length | Chrome
Full support
45
| Edge
Full support
79
| Firefox
Full support
33
| IE Full support 10 | Opera
Full support
32
| Safari Full support 6.1 | WebView Android Full support 45 | Chrome Android
Full support
45
| Firefox Android
Full support
33
| Opera Android
Full support
32
| Safari iOS Full support 7 | Samsung Internet Android No support No |
onaddtrack | Chrome
Full support
45
| Edge
Full support
79
| Firefox
Full support
33
| IE Full support 10 | Opera
Full support
32
| Safari Full support 6.1 | WebView Android Full support 45 | Chrome Android
Full support
45
| Firefox Android
Full support
33
| Opera Android
Full support
32
| Safari iOS Full support 7 | Samsung Internet Android No support No |
onchange | Chrome
Full support
45
| Edge
Full support
79
| Firefox
Full support
33
| IE Full support 10 | Opera
Full support
32
| Safari Full support 6.1 | WebView Android Full support 45 | Chrome Android
Full support
45
| Firefox Android
Full support
33
| Opera Android
Full support
32
| Safari iOS Full support 7 | Samsung Internet Android No support No |
onremovetrack | Chrome
Full support
45
| Edge
Full support
79
| Firefox
Full support
33
| IE Full support 10 | Opera
Full support
32
| Safari Full support 6.1 | WebView Android Full support 45 | Chrome Android
Full support
45
| Firefox Android
Full support
33
| Opera Android
Full support
32
| Safari iOS Full support 7 | Samsung Internet Android No support No |
removetrack event | Chrome
Full support
45
| Edge
Full support
79
| Firefox
Full support
33
| IE Full support 10 | Opera
Full support
32
| Safari Full support 6.1 | WebView Android Full support 45 | Chrome Android
Full support
45
| Firefox Android
Full support
33
| Opera Android
Full support
32
| Safari iOS Full support 7 | Samsung 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.