event.y 与 event.clientY在不同浏览器下的异同

In Chrome,

 event.y = event.clientY They are mouse event y location

In IE,

event.y != event.clientY  event.clinetY is mouse event y location. While event.y is not.

In Firefox,

There is no event.y.

所以，如果想要用鼠标的位置信息，建议使用event.clientY。