原文地址：JS倒计时代码作者：Millka

JS倒计时代码

第一种：精确到秒的javascript倒计时代码  



HTML代码:  

<formname="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>  
<scriptLANGUAGE="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Javascriptbegin-->  
<scriptlanguage="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("DigitalTime1()",1000)  

}  

}  
// -->  
</script>  
<!--倒计时Javascriptend-->  
<bodyonload=DigitalTime1()>  
<div id=LiveClock1></div>  

</body>

 

第三种：小时倒计时  



HTML代码:  
<SCRIPTLANGUAGE="JavaScript">  
<!--  
var maxtime = 60*60//一个小时，按秒计算，自己调整!  
function CountDown(){  
if(maxtime>=0){  
minutes =Math.floor(maxtime/60);  
seconds =Math.floor(maxtime`);  
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>  
<div id="timer"style="color:red"></div>  






第四种：最简倒计时  



HTML代码:  
<ScriptLanguage="JavaScript">   
<!--Begin   
　　var timedate= new Date("January14,2006");   
　　vartimes="研究生考试";   
　　var now = newDate();   
　　var date = timedate.getTime() -now.getTime();   
　　var time = Math.floor(date / (1000 * 60 * 60 *24));   
　　if (time >= 0);  
document.write("<li><fontcolor=#DEDBDE>现在离2006年"+times+"还有:<fontcolor=#ffffff><b>"+time+"</b></font>天</font></li>");  
// End -->  
</Script>  






第五种：最简倒计时二  



HTML代码:  
<script language="JavaScript"type="text/javascript">  
function djs(){  
var urodz= newDate("11/12/2008");　  
var now = new Date();  
var num  
var ile = urodz.getTime() -now.getTime();　　  
var dni = Math.floor(ile / (1000 * 60 * 60 *24));　　  
if (dni>1)　　  
num=dni+1
else if (dni == 1)　num=2　  
else if (dni == 0)　num=1
else num=0　  
document.write(num)　　  
}  
</script>  

距某某开幕式还有 [<script language="JavaScript"type="text/javascript">djs()</script>]天  
第五个：Javascript倒计时器 -采用系统时间自校验  
这次利用系统时间自校验倒计时, 无需手工调校使得倒计时更为精确,代码及详细注释如下:  

<spanid="clock">00:01:11:00</span>  
<input id="startB" type="button" value="startcountdown!"onclick="run()">  
<input id="endB" type="button" value="stopcountdown!"onclick="stop()">  
<br>  
<input id="diff"type="text">  
<input id="next"type="text">  
<scriptlanguage="Javascript">  

var normalelapse = 100;  
var nextelapse =normalelapse;  
varcounter;   
var startTime;  
var start =clock.innerText;   
var finish ="00:00:00:00";  
var timer = null;  

// 开始运行  
function run() {  
startB.disabled = true;  
endB.disabled = false;  
counter = 0;  
// 初始化开始时间  
startTime = newDate().valueOf();  

// nextelapse是定时时间,初始时为100毫秒  
// 注意setInterval函数: 时间逝去nextelapse(毫秒)后,onTimer才开始执行  
timer = window.setInterval("onTimer()",nextelapse);   
}  

// 停止运行  
function stop() {  
startB.disabled = false;  
endB.disabled = true;  
window.clearTimeout(timer);  
}  

window.onload = function(){  
endB.disabled = true;  
}  

// 倒计时函数  
function onTimer()  
{  

if (start == finish)  
{  
window.clearInterval(timer);  
alert("time is up!");  
return;  
}  

var hms = newString(start).split(":");  
var ms = newNumber(hms[3]);  
var s = newNumber(hms[2]);  
var m = newNumber(hms[1]);  
var h = newNumber(hms[0]);  
    
ms -= 10;  
if (ms <0)  
{  
ms = 90;  
s -= 1;  
if (s < 0)  
{  
    s =59;  
    m -=1;  
}  
    
if (m < 0)  
{  
    m =59;  
    h -=1;  
}  
}  

var ms = ms < 10 ? ("0" + ms) :ms;  
var ss = s < 10 ? ("0" + s) :s;  
var sm = m < 10 ? ("0" + m) :m;  
var sh = h < 10 ? ("0" + h) :h;  

start = sh + ":" + sm + ":" + ss + ":" +ms;  
clock.innerText = start;  

// 清除上一次的定时器  
window.clearInterval(timer);  

// 自校验系统时间得到时间差,并由此得到下次所启动的新定时器的时间nextelapse  
counter++;   
var counterSecs = counter *100;  
var elapseSecs = new Date().valueOf() -startTime;  
var diffSecs = counterSecs -elapseSecs;  
nextelapse = normalelapse +diffSecs;  
diff.value = counterSecs + "-" + elapseSecs + "=" +diffSecs;  
next.value = "nextelapse = " +nextelapse;  
if (nextelapse < 0) nextelapse =0;  

// 启动新的定时器  
timer = window.setInterval("onTimer()",nextelapse);   
}  
</script>