/*
author:alicn-wd-ym 
这里是所有js实现,代码比较少,主要还是取巧,利用了classname的关系 
*/ 
var videomenuTabIndex=1; 
var sTabList = document.getElementById("videomenuBox").getElementsByTagName("li"); 
for(var i=0;i<sTabList.length;i++){ 
var obj = sTabList[i].getElementsByTagName("a")[0]; 
sTabList[i].getElementsByTagName("a")[0].id="videomenuBtn_"+(i+1); 
if (obj.addEventListener) { 
obj.addEventListener( "mouseover", overvideomenu, false ); 
} 
else if (obj.attachEvent) { 
obj.attachEvent( "onmouseover", overvideomenu ); 
} 
} 
function overvideomenu(e){ 
e = window.event || e; 
var srcElement = e.srcElement || e.target; 
var newTabIndex=srcElement.id.replace("videomenuBtn_",""); 
var pos = srcElement.parentNode.className; 
if(newTabIndex==""||pos.indexOf("_h")!=-1)return; 
document.getElementById("videomenuBtn_"+videomenuTabIndex).parentNode.className=document.getElementById("videomenuBtn_"+videomenuTabIndex).parentNode.className.replace("_h",""); 
document.getElementById("x_"+videomenuTabIndex).className="hide"; 
document.getElementById("x_"+newTabIndex).className="cont_"+pos; 
srcElement.parentNode.className = pos+"_h"; 
videomenuTabIndex=newTabIndex; 
} 
  
<!--slidebox end-->