AudioTrackList.onchange

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AudioTrackList property onchange is an event handler which is called when the change event occurs, indicating that one or more of the AudioTrack s in the AudioTrackList have been enabled or disabled.

The event is passed into the event handler in the form of an 事件 object; the event doesn't provide any additional information. To determine the new state of media's tracks, you'll have to look at their AudioTrack.enabled 标志。

注意： You can also add a handler for the change event using addEventListener() .

句法

AudioTrackList.onchange = eventHandler;

值

Set onchange to a function that should be called whenever tracks are enabled or disabled on the media element.

范例

This snippet establishes a handler for the change event that looks at each of the tracks in the list, calling a function to update the state of a user interface control that indicates the current state of the track.

var trackList = document.querySelector("video").audioTracks;
trackList.onchange = function(event) {
  trackList.forEach(function(track) {
    updateTrackEnabledButton(track.id, track.enabled);
  });
};

updateTrackEnabledButton() , in this example, should be a function that finds a user interface control using the track's id (perhaps the app uses the track ID as the control element's ID) and the track's enabled flag to determine which state the control should be in now.

规范

规范	状态	注释
HTML 实时标准 The definition of 'AudioTrackList.onchange' in that specification.	实时标准
HTML5 The definition of 'AudioTrackList.onchange' in that specification.	推荐

浏览器兼容性

The compatibility table in 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
`onchange`	Chrome 45 Disabled 45 Disabled Disabled From version 45: this feature is behind the `enable-experimental-web-platform-features` preference (needs to be set to `enabled` ). To change preferences in Chrome, visit chrome://flags.	Edge 79 Disabled 79 Disabled Disabled From version 79: this feature is behind the `enable-experimental-web-platform-features` preference (needs to be set to `enabled` ). 不支持 12 — 79	Firefox 33	IE 10	Opera 32 Disabled 32 Disabled Disabled From version 32: this feature is behind the `enable-experimental-web-platform-features` preference (needs to be set to `enabled` ).	Safari 6.1	WebView Android 45	Chrome Android 45 Disabled 45 Disabled Disabled From version 45: this feature is behind the `enable-experimental-web-platform-features` preference (needs to be set to `enabled` ). To change preferences in Chrome, visit chrome://flags.	Firefox Android 33	Opera Android 32 Disabled 32 Disabled Disabled From version 32: this feature is behind the `enable-experimental-web-platform-features` preference (needs to be set to `enabled` ).	Safari iOS 7	Samsung Internet Android No

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完整支持
不支持
用户必须明确启用此特征。

元数据

最后修改： Mar 18, 2019

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