js 实现倒计时特效

<div id="tiao" style="width:559px; height:300px;"></div>

<!--脚本开始-->

<script language="javascript" type="text/javascript">

countDown(3);

function countDown(secs){

/* document.getElementById("tiao").style.backgroundImage="url(/tpl/Wap/default/common/xinnian/decode"+secs+".png)"; 

*/

 document.getElementById("tiao").innerHTML=secs;

 if(--secs>0)

  setTimeout("countDown("+secs+")",1000);

 }

 </script>