The AudioTrackList
method getTrackById()
returns the first AudioTrack
object from the track list whose id
matches the specified string. This lets you find a specified track if you know its ID string.
Syntax
var theTrack = AudioTrackList.getTrackById(id);
Paramters
id
- A
DOMString
indicating the ID of the track to locate within the track list.
Return value
An AudioTrack
object indicating the first track found within the AudioTrackList
whose id
matches the specified string. If no match is found, this method returns null
.
The tracks are searched in their natural order; that is, in the order defined by the media resource itself, or, if the resource doesn't define an order, the relative order in which the tracks are declared by the media resource.
Example
This example suggests a hypothetical game in which movies are used as cut-scenes or other key set pieces within the game. Each movie has one audio track for each character, as well as one for the music, sound effects, and so forth. This function allows the game to disable a specific character's audio in order to adjust the movie's performance based on occurrences within the game; if the character's dialog isn't relevant, it gets left out. Obviously that would require some clever graphic design to make work, but... it's a hypothetical game.
function disableCharacter(videoElem, characterName) { videoElem.audioTracks.getTrackById(characterName).enabled = false; }
This short function gets the AudioTrackList
containing the video's audio tracks using HTMLMediaElement.audioTracks
, then calls getTrackById()
on it, specifying the character's name. The resulting track's audio is then disabled by setting its enabled
flag to false
.
Specifications
Specification | Status | Comment |
---|---|---|
HTML Living Standard The definition of 'AudioTrackList.getTrackById()' in that specification. |
Living Standard | |
HTML5 The definition of 'AudioTrackList.getTrackById()' in that specification. |
Recommendation |
Browser compatibility
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
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 |
Legend
- Full support
- Full support
- No support
- No support
- User must explicitly enable this feature.
- User must explicitly enable this feature.