JavaScript--倒计时

<script>
var now=new Date();
var end=new Date(2009,6,1);
var ms=Math.floor((end.getTime()-now.getTime())/1000);
var d=Math.floor(ms/(60*60*24));
ms=ms%(60*60*24);
var h=Math.floor(ms/(60*60));
ms=ms%(60*60);
var m=Math.floor(ms/(60));
var s=ms%60;
document.write("距离放假还有："+'<br>'+d+"天"+h+"时"+m+"分"+s+"秒");
</script>