请教一下addEventListener第三个参数的意思？

element.addEventListener( type, listener, useCapture )

type
A string representing the event type being registered.

listener
The listener parameter takes an interface implemented by the user which contains the methods to be called when the event occurs.

useCapture
If true, useCapture indicates that the user wishes to initiate capture. After initiating capture, all events of the specified type will be dispatched to the registered EventListener before being dispatched to any EventTargets beneath them in the tree. Events which are bubbling upward through the tree will not trigger an EventListener designated to use capture.



这第三个参数到底什么意思啊？

aElem.addEventListener( "mouseover", handleFunc, false )

和

aElem.onmouseover = handleFunc

的意义是相同的。

前者是DOM2的规范，后者是旧的规范


最后一个参数用的少，而且很多地方介绍这个接口时都说明IE的attachEvent方法不支持 useCapture 参数