AudioTrackList.getTrackById()

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AudioTrackList 方法 getTrackById() 返回第一 AudioTrack object from the track list whose id matches the specified string. This lets you find a specified track if you know its ID string.

句法

var theTrack = AudioTrackList.getTrackById(id);

Paramters

id: DOMString indicating the ID of the track to locate within the track list.

返回值

AudioTrack object indicating the first track found within the AudioTrackList whose id matches the specified string. If no match is found, this method returns null .

The tracks are searched in their natural order; that is, in the order defined by the media resource itself, or, if the resource doesn't define an order, the relative order in which the tracks are declared by the media resource.

范例

This example suggests a hypothetical game in which movies are used as cut-scenes or other key set pieces within the game. Each movie has one audio track for each character, as well as one for the music, sound effects, and so forth. This function allows the game to disable a specific character's audio in order to adjust the movie's performance based on occurrences within the game; if the character's dialog isn't relevant, it gets left out. Obviously that would require some clever graphic design to make work, but... it's a hypothetical game.

function disableCharacter(videoElem, characterName) {
  videoElem.audioTracks.getTrackById(characterName).enabled = false;
}

This short function gets the AudioTrackList containing the video's audio tracks using HTMLMediaElement.audioTracks , then calls getTrackById() on it, specifying the character's name. The resulting track's audio is then disabled by setting its enabled flag to false .

规范

规范	状态	注释
HTML 实时标准 The definition of 'AudioTrackList.getTrackById()' in that specification.	实时标准
HTML5 The definition of 'AudioTrackList.getTrackById()' 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
`getTrackById`	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

图例

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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句法

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返回值

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图例

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