Web/API/MediaTrackConstraints/facingMode

The MediaTrackConstraints dictionary's facingMode property is a ConstrainDOMString describing the requested or mandatory constraints placed upon the value of the facingMode constrainable property.

If needed, you can determine whether or not this constraint is supported by checking the value of MediaTrackSupportedConstraints.facingMode as returned by a call to MediaDevices.getSupportedConstraints(). However, typically this is unnecessary since browsers will simply ignore any constraints they're unfamiliar with.

Because RTP doesn't include this information, tracks associated with a WebRTC RTCPeerConnection will never include this property.

Syntax

var constraintsObject = { facingMode: constraint };

constraintsObject.facingMode = constraint;

Value

An object based on ConstrainDOMString specifying one or more acceptable, ideal, and/or exact (mandatory) facing modes are acceptable for a video track.

An exact value in this case indicates that the specified facing mode is specifically required; for example:

var constraints = {
  facingMode: { exact: "user" }
};

This indicates that only a user-facing camera is acceptable; if there is no user-facing camera, or the user declines permission to use that camera, the media request will fail.

The following strings are permitted values for the facing mode. These may represent separate cameras, or they may represent directions in which an adjustable camera can be pointed.

"user": The video source is facing toward the user; this includes, for example, the front-facing camera on a smartphone.
"environment": The video source is facing away from the user, thereby viewing their environment. This is the back camera on a smartphone.
"left": The video source is facing toward the user but to their left, such as a camera aimed toward the user but over their left shoulder.
"right": The video source is facing toward the user but to their right, such as a camera aimed toward the user but over their right shoulder.

Example

See Example: Constraint exerciser in Capabilities, constraints, and settings for an example.

Specifications

Specification	Status	Comment
Media Capture and StreamsThe definition of 'facingMode' in that specification.	Candidate Recommendation	Initial specification.

Browser compatibility

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`facingMode`	Chrome Full support 59	Edge Full support ≤79	Firefox Full support 50	IE No support No	Opera Full support Yes	Safari ?	WebView Android Full support 59	Chrome Android Full support 59	Firefox Android Full support 50	Opera Android ?	Safari iOS ?	Samsung Internet Android Full support 7.0

Legend

Full support: Full support
No support: No support
Compatibility unknown: Compatibility unknown