//一个跳转提示页面
  <script type="text/javascript">  
 var s=5;
     function go(){
        document.getElementById("chan").innerHTML=s;
        s=s-1;
        if (s==0){
            window.location.href="http://www.imooc.com/";
        }
        window.setTimeout(go,1000);
    }
    go();
    
    function goBear(){
        window.history.back();
    }
 </script>
 <h3>操作成功</h3>
  <p><span id="chan">5</span>秒后返回到主页<a href="http://www.imooc.com/" onclick="goBear()" >返回</a></p>