网页中常见的10秒倒计时

 var i=10;
 var id=setInterval("fun1()",1000);
 function fun1(){
   if(i==0)
   {
       window.location.href="index.html";
       clearInterval(id);           
   }
   else
   {
       document.getElementById("span1").innerHTML=i;
       i--;
    }
  }