MediaDevices.getSupportedConstraints()

 

MediaDevices 接口的getSupportedConstraints()方法返回一个基于MediaTrackSupportedConstraints (en-US)的对象, 其成员字段都是客户端(user agent)所支持的约束属性(如帧率,窗口大小)。

语法

var supportedConstraints = navigator.mediaDevices.getSupportedConstraints();

参数

返回值

一个新的基于MediaTrackSupportedConstraints (en-US) 的对象用来监视客户端所支持的约束属性.因为只有客户端所支持的约束属性才能被展示在这个列表中 , 这些布尔值(Boolean)属性的每一个都为true。

示例

这个示例展示了你的客户端所支持的约束属性的列表。

let constraintList = document.getElementById("constraintList");
let supportedConstraints = navigator.mediaDevices.getSupportedConstraints();

for (let constraint in supportedConstraints) {
  if (supportedConstraints.hasOwnProperty(constraint)) {
    let elem = document.createElement("li");

    elem.innerHTML = "<code>" + constraint + "</code>";
    constraintList.appendChild(elem);
  }
}

结果

规范

规范 状态 备注
Media Capture and Streams
getSupportedConstraints()
Candidate Recommendation Initial definition.

浏览器支持情况

We're converting our compatibility data into a machine-readable JSON format. This compatibility table still uses the old format, because we haven't yet converted the data it contains. Find out how you can help! (en-US)

Feature Chrome Firefox (Gecko) Internet Explorer Microsoft Edge Opera Safari
Basic support (Yes) 50 (50) ? ? ? ?
Feature Android Android Webview Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile Chrome for Android
Basic support ? 48.0 (48) 50.0 (50) ? ? ? (Yes)