ConstrainDOMString

ConstrainDOMString dictionary is used to specify a constraint for a property whose value is a string. It allows you to specify one or more exact string values from which one must be the parameter's value, or a set of ideal values which should be used if possible. You can also specify a single string (or an array of strings) which the user agent will do its best to match once all more stringent constraints have been applied.

特性

The value of a ConstrainDOMString 可以是下列任一:

exact
Either a single DOMString which must be the value of the property, or an array of DOMString objects one of which must be the property's value. If the property can't be set to one of the listed values, matching will fail.
ideal
Either a single DOMString or an arrray of DOMString s specifying ideal values for the property. If possible, one of the listed values will be used, but if it's not possible, the user agent will use the closest possible match.

规范

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

Technically, ConstrainDOMString is actually based on an intermediary dictionary named ConstrainDOMStringParameters , which adds exact and ideal to DOMString . 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

更新 GitHub 上的兼容性数据
Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari Android webview Chrome for Android Firefox for Android Opera for Android Safari on iOS Samsung Internet
ConstrainDOMString 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