js动态改变时间

<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
 <script language="javascript">
     var t = null;
    t = setTimeout(time,1000);//开始执行
    function time()
    {
       clearTimeout(t);//清除定时器
       dt = new Date();
       var h=dt.getHours();
       var m=dt.getMinutes();
       var s=dt.getSeconds();
       document.getElementById("timeShow").innerHTML =  "现在的时间为："+h+"时"+m+"分<span style='color:red'>"+s+"秒</span>";
       t = setTimeout(time,1000); //设定定时器，循环执行             
    } 
  </script>
</head>
 
<body>
<label id="timeShow"></lable>

</body>
</html>