Js秒数倒计时(商品促销中多用)的实现代码

1、html页面元素：

2、js代码

<script language="javascript">
/**
 * 促销 秒数倒计时
 * http://www.jb200.com
*/
var startdate = new date($!datemillisecond);
var enddate = new date($!millisecond1);
var spantime = (enddate - startdate)/1000;
var expiredaystemp = $!expiredays;
function cal(){
spantime --;
var h = math.floor((spantime % (24*3600))/3600);
var m = math.floor((spantime % 3600)/(60));
var s = math.floor(spantime%60);
if((h+"").length==1){
h = "0" + h;
}
if((m+"").length==1){
m = "0" + m;
}
if((s+"").length==1){
s = "0" + s;
}
str = h + ":" + m + ":" + s;
document.getelementbyid("pad").innerhtml = str;
if(expiredaystemp==0&&h==0&&m==0&&s==0){
document.getelementbyid("limitedtimeoffers").style.display = "none";
}
}
window.onload = function(){
setinterval(cal, 1000);
}
</script>