From Xojo Documentation

Read-Only Property (As Boolean )
BooleanValue = aWebAnimator.YRotationSupported

New in 2010r4

Supported for all project types and targets.

Returns True if y-axis rotation animation is supported by the browser. If False, then the RotateY method does nothing.

Sample Code

Call RotateY if supported by the browser:

If Animator1.YRotationSupported Then
Animator1.RotateY(ImageView1, 180, 0.5)
End If