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
- WebRTC - the introductory page to the API
- Navigator.getUserMedia()