MediaDevices

这是一个实验中的功能
此功能某些浏览器尚在开发中,请参考浏览器兼容性表格以得到在不同浏览器中适合使用的前缀。由于该功能对应的标准文档可能被重新修订,所以在未来版本的浏览器中该功能的语法和行为可能随之改变。

The MediaDevices interface provides access to connected media input devices like cameras and microphones, as well as screensharing.

Properties

Inherits properties from its parent EventTarget.

Event handlers

MediaDevices.ondevicechange
Returns the event handler for the devicechange event type.

Methods

Inherits methods from its parent EventTarget.

EventTarget.addEventListener()
Registers an event handler to a specific event type.
MediaDevices.enumerateDevices()
Obtains an array of information about the media input and output devices available on the system.
MediaDevices.getUserMedia()
With the user's permission through a prompt, turns on a camera or screensharing and/or a microphone on the system and provides a MediaStream containing a video track and/or an audio track with the input.
EventTarget.removeEventListener()
Removes an event listener.

Example

'use strict';
// Put variables in global scope to make them available to the browser console.
var video = document.querySelector('video');
var constraints = window.constraints = {
  audio: false,
  video: true
};
var errorElement = document.querySelector('#errorMsg');
navigator.mediaDevices.getUserMedia(constraints)
.then(function(stream) {
  var videoTracks = stream.getVideoTracks();
  console.log('Got stream with constraints:', constraints);
  console.log('Using video device: ' + videoTracks[0].label);
  stream.onended = function() {
    console.log('Stream ended');
  };
  window.stream = stream; // make variable available to browser console
  video.srcObject = stream;
})
.catch(function(error) {
  if (error.name === 'ConstraintNotSatisfiedError') {
    errorMsg('The resolution ' + constraints.video.width.exact + 'x' +
        constraints.video.width.exact + ' px is not supported by your device.');
  } else if (error.name === 'PermissionDeniedError') {
    errorMsg('Permissions have not been granted to use your camera and ' +
      'microphone, you need to allow the page access to your devices in ' +
      'order for the demo to work.');
  }
  errorMsg('getUserMedia error: ' + error.name, error);
});
function errorMsg(msg, error) {
  errorElement.innerHTML += '<p>' + msg + '</p>';
  if (typeof error !== 'undefined') {
    console.error(error);
  }
}

Specifications

Specification Status Comment
Media Capture and Streams
MediaDevices
Editor's Draft Initial definition

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support (Yes) 36.0 (36.0) 未实现 未实现 未实现
enumerateDevices() 51.0 ? 未实现 未实现 未实现
Feature Android Android Webview Firefox Mobile (Gecko) Firefox OS IE Mobile Opera Mobile Safari Mobile Chrome for Android
Basic support 未实现 未实现 36.0 (36.0) 2.2 未实现 未实现 未实现 未实现
enumerateDevices() 未实现 未实现 ? ? 未实现 未实现 未实现 未实现

See also

文档标签和贡献者