files/en-us/web/api/mediatrackconstraints/width/index.md
{{APIRef("Media Capture and Streams")}}
The {{domxref("MediaTrackConstraints")}} dictionary's
width property is a ConstrainULong
describing the requested or mandatory constraints placed upon the value of the
{{domxref("MediaTrackSettings.width", "width")}} constrainable property.
If needed, you can determine whether or not this constraint is supported by checking the value of {{domxref("MediaTrackSupportedConstraints.width")}} as returned by a call to {{domxref("MediaDevices.getSupportedConstraints()")}}. However, typically this is unnecessary since browsers will ignore any constraints they're unfamiliar with.
If this value is a number, the user agent will attempt to obtain media whose width is
as close as possible to this number given the capabilities of the hardware and the other
constraints specified. Otherwise, the value of this ConstrainULong will
guide the user agent in its efforts to provide an exact match to the required width (if
exact is specified or both min and max are
provided and have the same value) or to a best-possible value.
See the Constraint exerciser example.
{{Specifications}}
{{Compat}}