HTMLMediaElement.textTracks
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.
Value
A TextTrackList
object representing the list of text tracks included in the media element. The list of tracks can be accessed using textTracks[n]
to get the nth text track from the object's list of text tracks, or using the textTracks
.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]);
}
}
Specifications
Specification |
---|
HTML Standard # dom-media-texttracks-dev |
Browser compatibility
BCD tables only load in the browser
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