js倒计时，秒倒计时，天倒计时

按天倒计时

HTML代码1:

<Script Language="JavaScript">   
<!-- Begin   
  var timedate= new Date("January 14,2006");   
  var times="研究生考试";   
  var now = new Date();   
  var date = timedate.getTime() - now.getTime();   
  var time = Math.floor(date / (1000 * 60 * 60 * 24));   
  if (time >= 0) ;  
  document.write("<li><font color=#DEDBDE>现在离2006年"+times+"还有: <font color=#ffffff><b>"+time +"</b></font> 天</font></li>");  
// End -->  
</Script>

HTML代码2:

<script language="JavaScript" type="text/javascript">  
function djs(){  
  var urodz= new Date("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

精确到秒的javascript倒计时代码

HTML代码:

<form name="form1">  
<div align="center" align="center">  
<center>离2013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>  

某某运动会，按时间提示不同的阶段

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("DigitalTime1()",1000)  
  }  

}  
// -->  
</script>  
<!--倒计时Javascript end-->  
<body onload=DigitalTime1()>  
<div id= LiveClock1></div>  

</body>

按小时倒计时

HTML代码:

<SCRIPT LANGUAGE="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%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>  
<div id="timer" style="color:red"></div>

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:

<span id="clock">00:01:11:00</span>  
<input id="startB" type="button" value="start countdown!" onclick="run()">  
<input id="endB" type="button" value="stop countdown!" onclick="stop()">  
<br>  
<input id="diff" type="text">  
<input id="next" type="text">  
<script language="Javascript">  
/* This notice must be untouched at all times.

countdown.js    v. 1.0
The latest version is available at
http://blog.csdn.net/yjgx007

Copyright (c) 2004 Xinyi.Chen. All rights reserved.
Created 7/30/2004 by Xinyi.Chen.  
Web: http://blog.csdn.net/yjgx007
E-Mail: chenxinyi1978@hotmail.com
Last modified: 7/30/2004

This program is free software;
you can redistribute it and/or modify it under the terms of the
GNU General Public License as published by the Free Software Foundation;

See the GNU General Public License
at http://www.gnu.org/copyleft/gpl.html for more details.
*/
var normalelapse = 100;  
var nextelapse = normalelapse;  
var counter;   
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 = new Date().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 = new String(start).split(":");  
  var ms = new Number(hms[3]);  
  var s = new Number(hms[2]);  
  var m = new Number(hms[1]);  
  var h = new Number(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>