MediaDevices.enumerateDevices() - Web APIs 编辑

The MediaDevices method enumerateDevices() requests a list of the available media input and output devices, such as microphones, cameras, headsets, and so forth. The returned Promise is resolved with a MediaDeviceInfo array describing the devices.

Syntax

var enumeratorPromise = navigator.mediaDevices.enumerateDevices();

Return value

A Promise that receives an array of MediaDeviceInfo objects when the promise is fulfilled. Each object in the array describes one of the available media input and output devices. The order is significant - the default capture devices will be listed first.

If enumeration fails, the promise is rejected.

Example

Here's an example of using enumerateDevices(). It outputs a list of the device IDs, with their labels if available.

if (!navigator.mediaDevices || !navigator.mediaDevices.enumerateDevices) {
  console.log("enumerateDevices() not supported.");
  return;
}

// List cameras and microphones.

navigator.mediaDevices.enumerateDevices()
.then(function(devices) {
  devices.forEach(function(device) {
    console.log(device.kind + ": " + device.label +
                " id = " + device.deviceId);
  });
})
.catch(function(err) {
  console.log(err.name + ": " + err.message);
});

This might produce:

videoinput: id = csO9c0YpAf274OuCPUA53CNE0YHlIr2yXCi+SqfBZZ8=
audioinput: id = RKxXByjnabbADGQNNZqLVLdmXlS0YkETYCIbg+XxnvM=
audioinput: id = r2/xw1xUPIyZunfV1lGrKOma5wTOvCkWfZ368XCndm0=

or if one or more MediaStreams are active or persistent permissions are granted:

videoinput: FaceTime HD Camera (Built-in) id=csO9c0YpAf274OuCPUA53CNE0YHlIr2yXCi+SqfBZZ8=
audioinput: default (Built-in Microphone) id=RKxXByjnabbADGQNNZqLVLdmXlS0YkETYCIbg+XxnvM=
audioinput: Built-in Microphone id=r2/xw1xUPIyZunfV1lGrKOma5wTOvCkWfZ368XCndm0=

Specifications

Browser compatibility

BCD tables only load in the browser

See also

• navigator.mediaDevices.getUserMedia()
• WebRTC - the introductory page to the API
• MediaStream API - the API for the media stream objects
• Taking webcam photos - a tutorial on using getUserMedia() for taking photos rather than video.