倒计时效果显示

<!DOCTYPE html>
<html>
<head>
   <title>倒计时效果显示</title>
   <meta http-equiv="Content-Type" content="text/html;charset=utf-8">
   <script type="text/javascript" src="https://code.jquery.com/jquery.js"></script>
   <script type="text/javascript">
   $(document).ready(function() {
       var interval = 1000;
       function ShowCountDown(year,month,day,divname)
       {
           function checkTime(i) {
               if (i<10) {
                   i="0"+i;
               }
               return i;
           }
           var now = new Date();
           var endDate = new Date(year, month-1, day);
           var leftTime=endDate.getTime()-now.getTime();
           var leftsecond = parseInt(leftTime/1000);
           var day1=Math.floor(leftsecond/(60*60*24));
           var hour=Math.floor((leftsecond-day1*24*60*60)/3600);
           var minute=Math.floor((leftsecond-day1*24*60*60-hour*3600)/60);
           var second=Math.floor(leftsecond-day1*24*60*60-hour*3600-minute*60);
           hour=checkTime(hour);
           minute=checkTime(minute);
           second=checkTime(second);
           var cc = document.getElementById(divname);
           cc.innerHTML = "仅剩："+day1+"天"+hour+"小时"+minute+"分"+second+"秒";
       }
       window.setInterval(function(){ShowCountDown(2015,9,20,'showTime');}, interval);
   })
   </script>
</head>
<body>
<p id="showTime">仅剩：0天02小时00分15秒</p>
</body>
</html>