This property indicates the rate of rotation around the Z axis -- in degrees per second -- in a DeviceRotationRate object. Syntax var alpha = deviceRotationRate.alpha; This property is read-only. Return value alpha A double indicating the rate of rotation around the Z axis, in degrees per second. See Accelerometer values explained for details. Specifications Specification Status Comment Device Orientation Events Working Draft Initial specification. Browser compatibility Desktop Mobile Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari (WebKit) Basic support ? ? ? ? ? Feature Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile Basic support ? ? ? ? ?