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The read-only textTracks
property on HTMLMediaElement
objects returns a TextTrackList
object listing all of the TextTrack
objects representing the media element's text tracks, in the same order as in the list of text tracks.
You can detect when tracks are added to and removed from an <audio>
or <video>
element using the addtrack
and removetrack
events. However, these events aren't sent directly to the media element itself. Instead, they're sent to the track list object of the HTMLMediaElement
that corresponds to the type of track that was added to the element
The returned list is live; that is, as tracks are added to and removed from the media element, the list's contents change dynamically. Once you have a reference to the list, you can monitor it for changes to detect when new text tracks are added or existing ones removed.
See Event handlers in TextTrackList to learn more about watching for changes to a media element's track list.
Syntax
var textTracks = mediaElement.textTracks;
Value
A TextTrackList
object representing the list of text tracks included in the media element. The list of tracks can be accessed using array notation, or using the object's getTrackById()
method.
Each track is represented by a TextTrack
object which provides information about the track.
Examples
We start with a <video>
that has several <track>
children
<video controls poster="/images/sample.gif"> <source src="sample.mp4" type="video/mp4"> <source src="sample.ogv" type="video/ogv"> <track kind="captions" src="sampleCaptions.vtt" srclang="en"> <track kind="descriptions" src="sampleDescriptions.vtt" srclang="en"> <track kind="chapters" src="sampleChapters.vtt" srclang="en"> <track kind="subtitles" src="sampleSubtitles_de.vtt" srclang="de"> <track kind="subtitles" src="sampleSubtitles_en.vtt" srclang="en"> <track kind="subtitles" src="sampleSubtitles_ja.vtt" srclang="ja"> <track kind="subtitles" src="sampleSubtitles_oz.vtt" srclang="oz"> <track kind="metadata" src="keyStage1.vtt" srclang="en" label="Key Stage 1"> <track kind="metadata" src="keyStage2.vtt" srclang="en" label="Key Stage 2"> <track kind="metadata" src="keyStage3.vtt" srclang="en" label="Key Stage 3"> </video>
The HTMLMediaElement.textTracks
returns a textTracksList
thru which we can iterate. Here we print all the properties of each English track to the console.
var tracks = document.querySelector('video').textTracks; for (var i = 0, L = tracks.length; i < L; i++) { /* tracks.length == 10 */ if (tracks[i].language == 'en') { console.dir(tracks[i]); } }
Properties & Methods
properties
- length
- Returns the number of text tracks in
TextTrackList
object.
methods
- getTrackById()
- The
getTrackById(id)
method returns the firstTextTrack
in theTextTrackList
object that matches the id, or null if there is no match.
Specifications
Specification | Status | Comment |
---|---|---|
HTML Living Standard The definition of 'HTMLMediaElement.textTracks' in that specification. |
Living Standard | No change from HTML5 |
HTML5 The definition of 'HTMLMediaElement.textTracks' in that specification. |
Recommendation | Initial definition. |
Browser compatibility
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
textTracks | Chrome Full support Yes | Edge Full support 12 | Firefox Full support Yes | IE ? | Opera Full support Yes | Safari Full support Yes | WebView Android ? | Chrome Android ? | Firefox Android ? | Opera Android ? | Safari iOS ? | Samsung Internet Android ? |
Legend
- Full support
- Full support
- Compatibility unknown
- Compatibility unknown
See also
- The interface defining it,
HTMLMediaElement
. <video>
and<audio>
VideoTrack
andVideoTrackList
AudioTrack
andAudioTrackList
- VideoTrackList
change
,addtrack
andremovetrack
events - Audio TrackList
change
,addtrack
andremovetrack
events