javascript 时间倒计时效果

<div id="divdown1"></div>

<script language="javascript" type="text/javascript">
　　var interval = 1000;  //倒计时间隔时间
　　function ShowCountDown(year,month,day,divname)
　　{
　　　　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=parseInt(leftsecond/(24*60*60*6));
　　　　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);
　　　　var cc = document.getElementById(divname);
　　　　cc.innerHTML = "脚本之家提示距离"+year+"年"+month+"月"+day+"日还有："+day1+"天"+hour+"小时"+minute+"分"+second+"秒";
}
　　window.setInterval(function(){ShowCountDown(2010,4,20,'divdown1');}, interval);
</script>