比较全的JavaScript倒计时脚本

JavaScript倒计时在Web中用得非常广泛，比如常见的团购啊、还有什么值得期待的事情，都可以用到倒计时。现在举了四个例子，比如时间长的倒计时，小时倒计时，最简的倒计时，还有秒表等等，应该可以满足大部分需求。

1. 比较长时间的倒计时

<script type="text/javascript">
startclock();
var timerID = null;
var timerRunning = false;
function showtime() {
	Today = new Date();
	var year = Today.getFullYear();
	document.getElementById("next_yeat").innerHTML = year + 1;
	var NowHour = Today.getHours();
	var NowMinute = Today.getMinutes();
	var NowMonth = Today.getMonth();
	var NowDate = Today.getDate();
	var NowYear = Today.getYear();
	var NowSecond = Today.getSeconds();
	if (NowYear <2000)
	NowYear=1900+NowYear;
	Today = null;
	Hourleft = 23 - NowHour
	Minuteleft = 59 - NowMinute
	Secondleft = 59 - NowSecond
	Yearleft = year - NowYear
	Monthleft = 12 - NowMonth - 1
	Dateleft = 31 - NowDate
	if (Secondleft<0)
	{
		Secondleft=60+Secondleft;
		Minuteleft=Minuteleft-1;
	}
	if (Minuteleft<0)
	{
		Minuteleft=60+Minuteleft;
		Hourleft=Hourleft-1;
	}
	if (Hourleft<0)
	{
		Hourleft=24+Hourleft;
		Dateleft=Dateleft-1;
	}
	if (Dateleft<0)
	{
		Dateleft=31+Dateleft;
		Monthleft=Monthleft-1;
	}
	if (Monthleft<0)
	{
		Monthleft=12+Monthleft;
		Yearleft=Yearleft-1;
	}
	Temp=Yearleft+'年, '+Monthleft+'月, '+Dateleft+'天, '+Hourleft+'小时, '+Minuteleft+'分, '+Secondleft+'秒';
	document.form1.left.value=Temp;
	timerID = setTimeout("showtime()",1000);
	timerRunning = true;
}
var timerID = null;
var timerRunning = false;
function stopclock () {
	if(timerRunning)
	clearTimeout(timerID);
	timerRunning = false;
}
function startclock () {
	stopclock();
	showtime();
}
// -->
</script>

　　

2. 小时倒计时（短时间倒计时）

<script type="text/javascript">
<!--
//一个小时，按秒计算，可以自己调整时间
var maxtime = 60*60
function CountDown()
{
	if(maxtime>=0)
	{
		minutes = Math.floor(maxtime/60);
		seconds = Math.floor(maxtime%60);
		msg = "距离结束还有 "+minutes+" 分 "+seconds+" 秒";
		document.all["timer"].innerHTML=msg;
		if(maxtime == 5*60) alert('注意，还有5分钟!');
		--maxtime;
	}
	else
	{
		clearInterval(timer);
		alert("时间到，结束!");
	}
}
timer = setInterval("CountDown()",1000);
//-->
</script>

　　转载：原文来自http://www.nowamagic.net/librarys/veda/detail/421