function supportsPointerEventsFn() {
  // check cache
  if (_supportsPointerEvents !== undefined) return _supportsPointerEvents;
  
  var element = document.createElement('x');
  element.style.cssText = 'pointer-events:auto';
  _supportsPointerEvents = (element.style.pointerEvents === 'auto');
  return _supportsPointerEvents;
}
Check if client supports pointer events.