比较全的JavaScript倒计时脚本[xyytit]

需要做一个功能，给特定的活动或者商品添加一个倒计时提示，在网上找了好些方法，总结了比较好的一些方法，以备后用：

1. 比较长时间的倒计时（如：距离2014年还有0年, 0月, 30天, 9小时, 41分, 17秒）

<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（如：距离结束还有 42 分 5 秒）

<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>

3. 最简倒计时（如：现在离 2014 还有: 30 天）

<script Language="JavaScript">    
<!-- Begin    
　　var timedate= new Date("January 14,2012");    
　　var times="2012";    
　　var now = new Date();    
　　var date = timedate.getTime() - now.getTime();    
　　var time = Math.floor(date / (1000 * 60 * 60 * 24));    
　　if (time >= 0) ;   
document.write("<p>现在离 "+times+" 还有: <b>"+time +"</b> 天</p>");   
// End -->   
</script>   

4. 秒表功能（如：00:01:11:00）

<script type="text/javascript">   
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>

原文网址：http://www.nowamagic.net/librarys/veda/detail/421