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• 句法
• 范例
• 规范
• 浏览器兼容性
• 另请参阅
• 相关话题

RTCPeerConnection property ontrack 是 EventHandler which specifies a function to be called when the track event occurs, indicating that a track has been added to the RTCPeerConnection . The function receives as input the event object, of type RTCTrackEvent ; this event is sent when a new incoming MediaStreamTrack has been created and associated with an RTCRtpReceiver object which has been added to the set of receivers on connection.

句法

RTCPeerConnection.ontrack = eventHandler;
					

值

Set ontrack to be a function you provide that accepts as input a RTCTrackEvent object describing the new track and how it's being used. This information includes the MediaStreamTrack object representing the new track, the RTCRtpReceiver and RTCRtpTransceiver , and a list of MediaStream objects which indicates which stream or streams the track is part of..

范例

This example, taken from the code for the article Signaling and video calling , connects the incoming track to the <video> element which will be used to display the incoming video.

pc.ontrack = function(event) {
  document.getElementById("received_video").srcObject = event.streams[0];
  document.getElementById("hangup-button").disabled = false;
};
					

The first line of our ontrack event handler takes the first stream in the incoming track and sets the srcobject attribute to that. This connects that stream of video to the element so that it begins to be presented to the user. The second line of code simply enables a "hang up" button, which the user can use to disconnect from the call.

规范

规范	状态	注释
WebRTC 1.0: Real-time Communication Between Browsers The definition of 'RTCPeerConnection.ontrack' 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
ontrack	Chrome 64	Edge ≤18	Firefox 22	IE No	Opera 43 43 Promise-based version. 不支持 37 — 43	Safari 11	WebView Android 64	Chrome Android 64	Firefox Android 44	Opera Android 43 43 Promise-based version. 不支持 37 — 43	Safari iOS Yes	Samsung Internet Android 6.0

图例

完整支持

完整支持

不支持

不支持

见实现注意事项。

另请参阅

• track event and its type, RTCTrackEvent .

元数据

• 最后修改： 2020 年 1 月 22 日

相关话题

1. WebRTC API
2. RTCPeerConnection
3. 构造函数

   1. RTCPeerConnection()
4. 特性

   1. canTrickleIceCandidates
   2. connectionState
   3. currentLocalDescription
   4. currentRemoteDescription
   5. getDefaultIceServers()
   6. iceConnectionState
   7. iceGatheringState
   8. localDescription
   9. onaddstream
   10. onconnectionstatechange
   11. ondatachannel
   12. onicecandidate
   13. oniceconnectionstatechange
   14. onicegatheringstatechange
   15. onidentityresult
   16. onidpassertionerror
   17. onidpvalidationerror
   18. onnegotiationneeded
   19. onpeeridentity
   20. onremovestream
   21. onsignalingstatechange
   22. ontrack
   23. peerIdentity
   24. pendingLocalDescription
   25. pendingRemoteDescription
   26. remoteDescription
   27. sctp
   28. signalingState
5. 方法

   1. addIceCandidate()
   2. addStream()
   3. addTrack()
   4. close()
   5. createAnswer()
   6. createDataChannel()
   7. createOffer()
   8. generateCertificate()
   9. getConfiguration()
   10. getIdentityAssertion()
   11. getReceivers()
   12. getSenders()
   13. getStats()
   14. getStreamById()
   15. getTransceivers()
   16. removeStream()
   17. removeTrack()
   18. restartIce()
   19. setConfiguration()
   20. setIdentityProvider()
   21. setLocalDescription()
   22. setRemoteDescription()
6. 事件

   1. addstream
   2. identityresult
   3. negotiationneeded
   4. removestream
   5. signalingstatechange
7. 继承：

   1. EventTarget
8. Related pages for WebRTC

   1. MediaDevices.getUserMedia()
   2. Navigator.mediaDevices
   3. RTCCertificate
   4. RTCDTMFSender
   5. RTCDTMFToneChangeEvent
   6. RTCDataChannel
   7. RTCDataChannelEvent
   8. RTCDtlsTransport
   9. RTCErrorEvent
   10. RTCIceCandidate
   11. RTCIceTransport
   12. RTCPeerConnectionIceErrorEvent
   13. RTCPeerConnectionIceEvent
   14. RTCRtpReceiver
   15. RTCRtpSender
   16. RTCRtpTransceiver
   17. RTCSctpTransport
   18. RTCSessionDescription
   19. RTCStatsEvent
   20. RTCStatsReport
   21. RTCTrackEvent