TextTrackList: addtrack event - Web APIs 编辑

The addtrack event is fired when a track is added to a TextTrackList.

Examples

Using addEventListener():

const mediaElement = document.querySelector('video, audio');

mediaElement.textTracks.addEventListener('addtrack', (event) => {
  console.log(`Text track: ${event.track.label} added`);
});

Using the onaddtrack event handler property:

const mediaElement = document.querySelector('video, audio');

mediaElement.textTracks.onaddtrack = (event) => {
  console.log(`Text track: ${event.track.label} added`);
};

Specifications

Browser compatibility

BCD tables only load in the browser

See also

• Related events: removetrack, change
• This event on VideoTrackList targets: addtrack
• This event on AudioTrackList targets: addtrack
• This event on MediaStream targets: addtrack
• Media Streams API
• WebRTC