<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>计时器</title> 
<script type="text/javascript">
   var i;
   function clock(){ 
      var time=new Date();                  
      document.getElementById("clock").value = time;
   }
    i =setInterval("clock()",1000); 
    function continue(){
    i=setInterval("clock()",1000); 
    }
</script> 
</head> 
<body>
  <form>
    <input type="text" id="clock" size="50"  />
    <input type="button" value="Stop" onclick="clearInterval(i)"/>
    <input type="button" value="start" onclick="continue()">
  </form>
</body>
</html>
文本框里什么也没有
continue是关键字来的,改一下函数名