MediaDevices

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This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for usage in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the specification changes.

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
The definition of 'MediaDevices' in that specification.
Editor's Draft Initial definition

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support (Yes) 36.0 (36.0) No support No support No support
enumerateDevices() 51.0 ? No support No support No support
Feature Android Android Webview Firefox Mobile (Gecko) Firefox OS IE Mobile Opera Mobile Safari Mobile Chrome for Android
Basic support No support No support 36.0 (36.0) 2.2 No support No support No support No support
enumerateDevices() No support No support ? ? No support No support No support No support

See also

文档标签和贡献者

 此页面的贡献者: Victorystick
 最后编辑者: Victorystick,