在此页

• 句法
• 范例
• 规范
• 浏览器兼容性
• 另请参阅
• 相关话题

RTCPeerConnection 接口的 onnegotiationneeded property is an EventListener which specifies a function which is called to handle the negotiationneeded event when it occurs on an RTCPeerConnection instance. This event is fired when a change has occurred which requires session negotiation. This negotiation should be carried out as the offerer, because some session changes cannot be negotiated as the answerer.

Most commonly, the negotiationneeded event is fired after a send track is added to the RTCPeerConnection . If the session is modified in a manner that requires negotiation while a negotiation is already in progress, no negotiationneeded event will fire until negotiation completes, and only then if negotiation is still needed.

句法

RTCPeerConnection.onnegotiationneeded = eventHandler;
					

值

This should be set to a function you provide which is passed a single parameter: an 事件 object containing the negotiationneeded event. There's no additional information provided in the event; anything you need, you can get by examining the 特性对于 RTCPeerConnection .

范例

This example, derived from the example in Signaling and video calling , establishes a handler for negotiationneeded events to handle creating an offer, configuring the local end of the connection, and sending the offer to the remote peer.

pc.onnegotiationneeded = function() {
  pc.createOffer().then(function(offer) {
    return pc.setLocalDescription(offer);
  })
  .then(function() {
      // Send the offer to the remote peer through the signaling server
    });
  })
  .catch(reportError);
}
					

First, it creates the offer by calling createOffer() . When that succeeds, the offer is passed into setLocalDescription() to set the local description for the connection. Once that's succeeded in turn, the offer can be sent to the signaling server for delivery to the remote peer.

规范

规范	状态	注释
WebRTC 1.0: Real-time Communication Between Browsers The definition of 'RTCPeerConnection.onnegotiationneeded' 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
onnegotiationneeded	Chrome 24	Edge 15	Firefox 22	IE No	Opera 43 43 Promise-based version. 不支持 37 — 43	Safari 11	WebView Android Yes	Chrome Android Yes	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

• negotiationneeded event and its type, 事件 .

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