无意中在一段源码里看到event.currentTarget这个属性，这个与熟悉的event.target还是有所差别的。

event.target是指事件发生的源，在哪个元素上发生的。event.currentTarget 就是通过addEventListener绑定的DOM元素。事件是可以通过冒泡进行传递的。通过冒泡触发的事件event.target 跟event.currentTarget是不相同的元素。

引用网上的一段英文：Event objects also have target properties that reference the actual object which dispatched the event. In some cases, the target may not be the object for which you have registered a listener. This can occur when the object for which you have registered a listener contains a child component that also dispatches the same event (and the event bubbles). If you want to ensure that you are getting a reference to the object for which the listener is registered to listen for the event, use the currentTarget property。

event.currentTarget与event.target