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• 句法
• 范例
• 规范
• 浏览器兼容性
• 相关话题

active 只读特性在 MediaStream interface returns a Boolean value which is true if the stream is currently active; otherwise, it returns false . A stream is considered active if at least one of its MediaStreamTrack s is not in the MediaStreamTrack.ended state. Once every track has ended, the stream's active 特性变为 false .

句法

var isActive = MediaStream.active;
					

值

A Boolean value which is true if the stream is currently active; otherwise, the value is false .

范例

In this example, a new stream whose source is the user's local camera and microphone is requested using getUserMedia() . When that stream becomes available (that is, when the returned Promise is fulfilled, a button on the page is updated based on whether or not the stream is currently active.

var promise = navigator.mediaDevices.getUserMedia({
  audio: true,
  video: true
});
promise.then(function(stream) {
  var startBtn = document.querySelector('#startBtn');
  startBtn.disabled = stream.active;
};)
					

规范

规范	状态	注释
媒体捕获和流 The definition of 'active' in that specification.	候选推荐	初始定义。

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
active	Chrome 45	Edge 12	Firefox 52	IE No	Opera No	Safari Yes	WebView Android 45	Chrome Android 45	Firefox Android 52	Opera Android No	Safari iOS Yes	Samsung Internet Android 5.0

图例

完整支持

完整支持

不支持

不支持

元数据

• 最后修改： 2020 年 1 月 22 日

相关话题

1. Media Streams API
2. MediaStream
3. 构造函数

   1. MediaStream()
4. 特性

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

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

   1. addtrack
   2. removetrack
7. 继承：

   1. EventTarget
8. Related pages for Media Capture and Streams

   1. AudioStreamTrack
   2. BlobEvent
   3. CanvasCaptureMediaStream
   4. ConstrainBoolean
   5. ConstrainDOMString
   6. ConstrainDouble
   7. ConstrainLong
   8. DoubleRange
   9. HTMLCanvasElement.captureStream()
   10. LongRange
   11. MediaDevices
   12. MediaStreamTrack
   13. MediaStreamTrackEvent
   14. MediaTrackCapabilities
   15. MediaTrackConstraints
   16. MediaTrackSettings
   17. MediaTrackSupportedConstraints
   18. Navigator.mediaDevices
   19. NavigatorUserMedia
   20. NavigatorUserMediaError
   21. VideoStreamTrack
   22. navigator.mediaDevices.getUserMedia()