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";
}
}