VideoTrackList: change event - Web APIs 编辑

The change event is fired when a video track is made active or inactive, for example by changing the track's selected property.

Examples

Using addEventListener():

const videoElement = document.querySelector('video');
videoElement.videoTracks.addEventListener('change', (event) => {
    console.log(`'${event.type}' event fired`);
});

// changing the value of `selected` will trigger the `change` event
const toggleTrackButton = document.querySelector('.toggle-track');
toggleTrackButton.addEventListener('click', () => {
  const track = videoElement.videoTracks[0];
  track.selected = !track.selected;
});

Using the onchange event handler property:

const videoElement = document.querySelector('video');
videoElement.videoTracks.onchange = (event) => {
    console.log(`'${event.type}' event fired`);
};

// changing the value of `selected` will trigger the `change` event
const toggleTrackButton = document.querySelector('.toggle-track');
toggleTrackButton.addEventListener('click', () => {
  const track = videoElement.videoTracks[0];
  track.selected = !track.selected;
});

Specifications

Browser compatibility

BCD tables only load in the browser

See also

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