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 TextTrackList events to learn more about watching for changes to a media element's track list.
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 n-th 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.
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 through which we can iterate. Here we print all the properties of each English track to the console.
const tracks = document.querySelector("video").textTracks;
for (const track of tracks) {
if (track.language === "en") {
console.dir(track);
}
}