鼠标操作某一对象时
1.鼠标点击
onclick
2.鼠标双击
ondblclick
3.鼠标按下
onmousedown
4.鼠标抬起
onmouseup
5.鼠标移动
onmousemove
6.鼠标移入
onmouseenter
6.鼠标移入2
onmouseover
7.鼠标移出
onmouseout
8.鼠标移出2
onmouseleave
9.鼠标滚轮
onmousewheel
例子：
