//切换菜单
function nav(thisobj,num){
if(thisobj.classname == "at")return;
var tabobj = thisobj.parentnode.id;
var tablist = document.getelementbyid(tabobj).getelementsbytagname("li");
for(i=0; i <tablist.length; i++)
{
  if (i == num)
  {
   thisobj.classname = "at"; 
      document.getelementbyid(tabobj+"_c_"+i).style.display = "block";
  }else{
   tablist[i].classname = "not"; 
   document.getelementbyid(tabobj+"_c_"+i).style.display = "none";
  }
} 
}
function tts(thisobj,num){
if(thisobj.classname == "at")return;
var tabobj = thisobj.parentnode.id;
var tablist = document.getelementbyid

(tabobj).getelementsbytagname("li");
for(i=0; i <tablist.length; i++)
{
  if (i == num)
  {
   thisobj.classname = "at"; 
      document.getelementbyid(tabobj+"_c_"+i).style.display = 

"block";
  }else{
   tablist[i].classname = "lis"; 
   document.getelementbyid(tabobj+"_c_"+i).style.display = 

"none";
  }
} 
}