deltaX property

num deltaX
@DomName('WheelEvent.deltaX')

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

See also:

WheelEvent.deltaX from the W3C.

Implementation 

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