RTCPeerConnection: iceconnectionstatechange event

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用法注意事项
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规范
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An iceconnectionstatechange event is sent to an RTCPeerConnection object each time the ICE connection state changes during the negotiation process. The new ICE connection state is available in the object's iceConnectionState } property.

冒泡	No
可取消	No
接口	`事件`
事件处理程序特性	`oniceconnectionstatechange`

One common task performed by the iceconnectionstatechange event listener: to trigger ICE restart when the state changes to failed 。见 ICE restart in Lifetime of a WebRTC session 了解进一步信息。

用法注意事项

A successful connection attempt will typically involve the state starting at new , then transitioning through checking ，那么 connected , and finally completed . However, under certain circumstances, the connected state can be skipped, causing a connection to transition directly from the checking state to completed . This can happen when only the last checked candidate is successful, and the gathering and end-of-candidates signals both occur before the successful negotiation is completed.

ICE connection state during ICE restarts

When an ICE restart is processed, the gathering and connectivity checking process is started over from the beginning, which will cause the iceConnectionState to transition to connected if the ICE restart was triggered while in the completed state. If ICE restart is initiated while in the transient disconnected state, the state transitions instead to checking , essentially indicating that the negotiation is ignoring the fact that the connection had been temporarily lost.

State transitions as negotiation ends

When the negotiation process runs out of candidates to check, the ICE connection transitions to one of two states. If no suitable candidates were found, the state transitions to failed . If at least one suitable candidate was successfully identified, the state transitions to completed . The ICE layer makes this determination upon receiving the end-of-candidates signal, which is provided by caling addIceCandidate() with a candidate whose candidate property is an empty string (""), or by setting the RTCPeerConnection property canTrickleIceCandidates to false .

范例

An event handler for this event can be added using the RTCPeerConnection.oniceconnectionstatechange property or by using addEventListener() 在 RTCPeerConnection .

In this example, a handler for iceconnectionstatechange is set up to update a call state indicator by using the value of iceConnectionState to create a string which corresponds to the name of a CSS class that we can assign to the status indicator to cause it to reflect the current state of the connection.

pc.addEventListener("iceconnectionstatechange", ev => {
  let stateElem = document.querySelector("#call-state");
  stateElem.className = `${pc.iceConnectionState}-state`;
}, false);

This can also be written as:

pc.oniceconnectionstatechange = ev => {
  let stateElem = document.querySelector("#call-state");
  stateElem.className = `${pc.iceConnectionState}-state`;
}

规范

规范	状态	注释
WebRTC 1.0: Real-time Communication Between Browsers The definition of 'iceconnectionstatechange' in that specification.	候选推荐

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
`iceconnectionstatechange` event	Chrome 28	Edge 15	Firefox 22	IE No	Opera 43	Safari 11	WebView Android Yes	Chrome Android 28	Firefox Android 44	Opera Android 43	Safari iOS ?	Samsung Internet Android 6.0

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用法注意事项

ICE connection state during ICE restarts

State transitions as negotiation ends

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