搞定mouseover和mouseout兼容性的代码

gistfile1.js

function isMouseLeaveOrEnter(e, handler) {
  if (e.type != 'mouseout' && e.type != 'mouseover') return false;
  var reltg = e.relatedTarget ? e.relatedTarget : e.type == 'mouseout' ? e.toElement : e.fromElement;
  while (reltg && reltg != handler)
    reltg = reltg.parentNode;
  return (reltg != handler);
}