js倒计时代码

<div class="f14" id="kdsdate"></div>
<SCRIPT language=JavaScript>
 var myDay= new Date("09-15-2013"); 
 var now = new Date();
 var date = myDay.getTime() - now.getTime();
 var time = Math.floor(date / (1000 * 60 * 60 * 24));
 timegoto=-time;
 if (time >= 0) {
 document.getElementById("kdsdate").innerHTML=time;
}else{
 
 document.getElementById("kdsdate").innerHTML="0";
 }
</SCRIPT>