The addtrack event is fired when a new MediaStreamTrack object has been added to a MediaStream.

This event is not cancelable and does not bubble.

Use the event name in methods like addEventListener(), or set an event handler property.

addEventListener("addtrack", (event) => {});

onaddtrack = (event) => {};

A MediaStreamTrackEvent. Inherits from Event.

Also inherits properties from its parent interface, Event.

MediaStreamTrackEvent.track Read only

A MediaStreamTrack object representing the track which was added to the stream.

Using addEventListener():

const stream = new MediaStream();

stream.addEventListener("addtrack", (event) => {
  console.log(`New ${event.track.kind} track added`);
});

Using the onaddtrack event handler property:

const stream = new MediaStream();

stream.onaddtrack = (event) => {
  console.log(`New ${event.track.kind} track added`);
};

• Related events: removetrack
• This event on AudioTrackList targets: addtrack
• This event on VideoTrackList targets: addtrack
• Media Capture and Streams API
• WebRTC