<span class="time"></span>
<script>
 var t = 120;   //60秒后跳转
 var time = document.getElementsByClassName("time")[0];
 
 function fun() {
  t--;
  time.innerHTML = t;
  if(t <= 0) {
   location.href = "跳转的网址";
   clearInterval(inter);
  }
 }
 var inter = setInterval("fun()", 1000);
</script>