在此页

• 特性
• 规范
• 浏览器兼容性
• 另请参阅
• 相关话题

ConstrainBoolean dictionary is used to specify a constraint for a property whose value is a Boolean value. You can specify an exact value which must be matched, an ideal value that should be matched if at all possible, and a fallback value to attempt to match once all more specific constraints have been applied.

特性

exact

A Boolean which indicates a value the property must have.

ideal

A Boolean value indicating the ideal, but not required, value the property should ideally have. If possible, this value will be used, but the user agent will use the other value if it needs to in order to come up with a workable configuration.

You can also specify the value of the property as simply true or false , in which case the user agent will use that value if possible once all efforts have been made to match the exact and ideal values for other properties.

规范

规范	状态	注释
媒体捕获和流 The definition of 'ConstrainBoolean' in that specification.	候选推荐	初始定义

Technically, ConstrainBoolean is actually based on an intermediary dictionary named ConstrainBooleanParameters , which adds exact and ideal to the simple Boolean type. However, for the sake of documentation clarity, the intermediate type (present only because of quirks in WebIDL syntax) is ignored here.

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
ConstrainBoolean	Chrome Yes	Edge ≤79	Firefox 50	IE No	Opera Yes	Safari ?	WebView Android Yes	Chrome Android Yes	Firefox Android 50	Opera Android Yes	Safari iOS ?	Samsung Internet Android Yes

图例

完整支持

完整支持

不支持

不支持

兼容性未知 ?

兼容性未知

另请参阅

• Media Capture and Streams API
• Capabilities, constraints, and settings
• MediaTrackConstraints
• MediaTrackCapabilities
• MediaTrackSupportedConstraints

元数据

• 最后修改： 2020 年 1 月 22 日

相关话题

1. Media Streams API
2. ConstrainBoolean
3. Related pages for Media Capture and Streams

   1. AudioStreamTrack
   2. BlobEvent
   3. CanvasCaptureMediaStream
   4. ConstrainDOMString
   5. ConstrainDouble
   6. ConstrainLong
   7. DoubleRange
   8. HTMLCanvasElement.captureStream()
   9. LongRange
   10. MediaDevices
   11. MediaStream
   12. MediaStreamTrack
   13. MediaStreamTrackEvent
   14. MediaTrackCapabilities
   15. MediaTrackConstraints
   16. MediaTrackSettings
   17. MediaTrackSupportedConstraints
   18. Navigator.mediaDevices
   19. NavigatorUserMedia
   20. NavigatorUserMediaError
   21. VideoStreamTrack
   22. navigator.mediaDevices.getUserMedia()