第一种：精确到秒的javascript倒计时代码  



HTML代码:  

<form name="form1">  
<div align="center" align="center">  
<center>离2010年还有:<br>  
<input type="textarea" name="left" size="35" style="text-align: center">  
</center>  
</div>  
</form>  
<script LANGUAGE="javascript">  
startclock()  
var timerID = null;  
var timerRunning = false;  
function showtime() {  
Today = new Date();  
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 = 2009 - 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>  






第二种：某某运动会  



HTML代码:  
<!--倒计时Javascript begin-->  
<script language="JavaScript">  
<!--   
function DigitalTime1()  
{   
var deadline= new Date("08/13/2007") //开幕倒计时  
var symbol="8月13日"
var now = new Date()  
var diff = -480 - now.getTimezoneOffset() //是北京时间和当地时间的时间差  
var leave = (deadline.getTime() - now.getTime()) + diff*60000
var day = Math.floor(leave / (1000 * 60 * 60 * 24))  
var hour = Math.floor(leave / (1000*3600)) - (day * 24)  
var minute = Math.floor(leave / (1000*60)) - (day * 24 *60) - (hour * 60)  
var second = Math.floor(leave / (1000)) - (day * 24 *60*60) - (hour * 60 * 60) - (minute*60)  

var deadline_2= new Date("08/13/2004") //开幕后计时  
var symbol_2="8月13日"
var now_2 = new Date()  
var diff_2 = -480 - now.getTimezoneOffset() //是北京时间和当地时间的时间差  
var leave_2 = (now_2.getTime() - deadline_2.getTime()) + diff_2*60000
var day_2 = Math.floor(leave_2 / (1000 * 60 * 60 * 24))  
var hour_2 = Math.floor(leave_2 / (1000*3600)) - (day_2 * 24)  
var minute_2 = Math.floor(leave_2 / (1000*60)) - (day_2 * 24 *60) - (hour_2 * 60)  
var second_2 = Math.floor(leave_2 / (1000)) - (day_2 * 24 *60*60) - (hour_2 * 60 * 60) - (minute_2*60)  
   
day=day+1;  
day_2=day_2+1;  

if (day>0) //还未开幕  
{  
//LiveClock1.innerHTML = "现在"+symbol+"天"  
LiveClock1.innerHTML = "<font
setTimeout("DigitalTime1()",1000)  
}  

if (day<0) //已经开幕  
{  
//LiveClock1.innerHTML = "现在离"+symbol+"还有"+day+"天"+hour+"小时"+minute+"分"+second +"秒"  
LiveClock1.innerHTML = "<font
setTimeout("DigitalTime1()",1000)  

}  

if (day==0) //正在开幕  
{  
//LiveClock1.innerHTML = "现在"+symbol+"天"  
LiveClock1.innerHTML = "<font
setTimeout("DigitalTime1()",1000)  
}  

   
   
if (day<0 & day_2>19) //某某运动会结束  
{  
//LiveClock1.innerHTML = "现在离"+symbol+"还有"+day+"天"+hour+"小时"+minute+"分"+second +"秒"  
LiveClock1.innerHTML = "<font
setTimeout(&quo