deltaY property

num deltaY

The amount that is expected to scroll vertically, in units determined by deltaMode.

See also:

WheelEvent.deltaY from the W3C.

Implementation 

num get deltaY {
  if (JS('bool', '#.deltaY !== undefined', this)) {
    // W3C WheelEvent
    return this._deltaY;
  }
  throw new UnsupportedError('deltaY is not supported');
}