function setTab(m,n){
var tli=document.getElementById("menu"+m).getElementsByTagName("li");
var mli=document.getElementById("main"+m).getElementsByTagName("ul");
for(i=0;i<tli.length;i++){
  tli[i].className=i==n?"hover":"";
  mli[i].style.display=i==n?"block":"none";
}
N=n;
}
//自动循环切换
/*
var N=0,soptTime=3000,timer;//3000ms=3s
onload=function(){setTimeout(nextTab,soptTime)}
function nextTab(){
j=document.getElementById("menu1").getElementsByTagName("li").length;
N++;
if (N>=j) N=0;
setTab(1,N)
timer=setTimeout(nextTab,soptTime)
}
*/