为什么我这个鼠标移开没有隐藏二级菜单？
<script>
window.onload=function(){
var aLi=document.getElementsByTagName('li');
for(var i=0; i<aLi.length; i++){
aLi[i].onmouseover=function(){
//鼠标经过一级菜单，二级菜单动画下拉显示出来
var oSubNav = this.getElementsByTagName('ul')[0];
if(oSubNav) {
var This = oSubNav;
clearInterval(This.time);
This.time=setInterval(function(){
This.style.height=This.offsetHeight+16+"px";
if(This.offsetHeight>=120)
clearInterval(This.time);
},30)
}
}
//鼠标离开菜单，二级菜单动画收缩起来。
aLi[i].onmouseout=function(){
var oSubNav=this.getElementsByTagName('ul')[0];
if(oSubNav){
var This = oSubNav;
clearInterval(This.time);
This.time=setInterval(function(){
This.style.height=This.offSetHeight-16+"px";
if(This.offsetHeight<=0){
This.style.height=0;
This.style.overflow = hidden;
clearInterval(This.time);
}
},30)
}
}
}
}
</script>
