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• 句法
• 范例
• 规范
• 浏览器兼容性
• 另请参阅
• 相关话题

MediaStream.onaddtrack property is an EventHandler which specifies a function to be called when the addtrack event occurs on a MediaStream instance. This happens when a new track of any kind is added to the media stream. This event is fired when the browser adds a track to the stream (such as when a RTCPeerConnection is renegotiated or a stream being captured using HTMLMediaElement.captureStream() gets a new set of tracks because the media element being captured loaded a new source.

addtrack event does not get fired when JavaScript code explicitly adds tracks to the stream (by calling addTrack() ).

句法

MediaStream.onaddtrack = eventHandler;
					

值

This should be set to a function which you provide that accepts as input a MediaStreamTrackEvent object representing the addtrack event which has occurred. The MediaStreamTrack representing the track which was added is specified in the event's track 特性。

范例

This example adds a listener which, when a new track is added to the stream, appends a new item to a list of tracks; the new item shows the track's kind ( "audio" or "video" ) 和 label .

stream.onaddtrack = function(event) {
  let trackList = document.getElementById("tracks");
  let label = document.createElement("li");
  label.innerHTML = event.track.kind + ": " + event.track.label;
  trackList.appendChild(label);
};
					

规范

规范	状态	注释
媒体捕获和流 The definition of 'MediaStream.onaddtrack' in that specification.	候选推荐	最初的规范。

浏览器兼容性

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request. 更新 GitHub 上的兼容性数据

	桌面						移动
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
onaddtrack	Chrome 26	Edge 12	Firefox 50	IE 不支持 No	Opera 不支持 No	Safari Yes	WebView Android 37	Chrome Android 26	Firefox Android 50	Opera Android 不支持 No	Safari iOS Yes	Samsung Internet Android 1.5

图例

完整支持

完整支持

不支持

不支持

另请参阅

• addtrack event and its type, MediaStreamTrackEvent .

元数据

• 最后修改： 2019 年 3 月 23 日

相关话题

1. MediaStream
2. 构造函数

   1. MediaStream()
3. 特性

   1. active
   2. ended
   3. id
   4. onaddtrack
   5. onremovetrack
4. 方法

   1. addTrack()
   2. clone()
   3. getAudioTracks()
   4. getTrackById()
   5. getTracks()
   6. getVideoTracks()
5. 事件

   1. addtrack
   2. removetrack
6. 继承：

   1. EventTarget