javaScript timer控制

 <script type="text/javascript">
         var num = 0;  
         //间隔一秒循环执行 
         var id = setInterval(function () 
         {
             num = num + 1;
             document.getElementById("ss").value = num;
         }, 1000);

         //间隔一秒执行一次     
         var ids = setTimeout(function () {
             num = num + 1;
             document.getElementById("ss").value = num;
         }, 1000);
         //停止方法
         function stopModth() {
             clearInterval(id);
             clearTimeout(ids);
         }       
    </script>