function ExChgClsName(Obj,NameA,NameB){
  var Obj=document.getElementById(Obj)?document.getElementById(Obj):Obj;
  Obj.className=Obj.className==NameA?NameB:NameA;
 }
 function showMenu(iNo){
 ExChgClsName("Menu_"+iNo,"MenuBox","MenuBox2");
 }