DeviceMotionEvent

accelerationx?
y?
z?
accelerationIncludingGravityx?
y?
z?
rotationRatealpha?
beta?
gamma?
interval?

DeviceOrientationEvent

alpha?
beta?
gamma?

According to Apple's ref. (#2 below):
The angles of rotation do not represent the real world orientation. They are defined as offset from an arbitrary direction.

  1. Apple: DeviceMotionEvent Class Reference
  2. Apple: DeviceOrientationEvent Class Reference
  3. W3C: DeviceOrientation Event Specification