src:http://hi.baidu.com/��Ҫ��/blog/item/7d70b8eedfc91bc8b21cb1c4.html
 <script type="text/javascript" language="javascript">

        var target=[]
        var time_id=[]
       
        function show_date_time_0()
        {
            setTimeout("show_date_time_0()", 1000);
            for (var i=0,j=target.length;i<j;i++)
            {
                today=new Date();         
                //计算目标时间与当前时间间隔(毫秒数)
                var timeold=target[i]-today.getTime(); //getTime 方法返回一个整数值，这个整数代表了从 1970 年 1 月 1 日开始计算到 Date 对象中的时间之间的毫秒数。
               
                //计算目标时间与当前时间的秒数
                var sectimeold=timeold/1000;
               
                //计算目标时间与当前时间的秒数(整数)
                var secondsold=Math.floor(sectimeold);
               
                //计算一天的秒数
                var msPerDay=24*60*60*1000;
              
                //得到剩余天数
                var e_daysold=timeold/msPerDay;
                 //得到剩余天数(整数)
                var daysold=Math.floor(e_daysold);
               
                //得到剩余天数以外的小时数
                var e_hrsold=(e_daysold-daysold)*24;
                 //得到剩余天数以外的小时数(整数)
                var hrsold=Math.floor(e_hrsold);
               
                //得到尾剩余分数
                var e_minsold=(e_hrsold-hrsold)*60;
                //得到尾剩余分数(整数)
                minsold=Math.floor((e_hrsold-hrsold)*60);
               
                //得到尾剩余秒数(整数)
                seconds=Math.floor((e_minsold-minsold)*60);
                if (daysold<0)
                {
                    document.getElementByIdx_x(time_id[i]).innerHTML="逾期,倒计时已经失效";
                }
                else
                {
                    //天数取三位,不足时前边补0
                    if (daysold<10) { daysold="0"+daysold }
                    //天数取三位,不足时前边补0
                    if (daysold<100) { daysold="0"+daysold }
                   
                    //小时取两位,不足补0
                    if (hrsold<10) { hrsold="0"+hrsold }
                    //分数取两位,不足补0
                    if (minsold<10) {minsold="0"+minsold}
                    //秒数取两位,不足补0
                    if (seconds<10) {seconds="0"+seconds}
                   
                    //小于三天时,字体为红色
                    if (daysold<3) {
                        document.getElementByIdx_x(time_id[i]).innerHTML="<font color=red>"+hrsold+"小时"+minsold+"分"+seconds+"秒</font>";
                    }
                    else
                    {
                        //document.getElementByIdx_x(time_id[i]).innerHTML=daysold+"天"+hrsold+"小时"+minsold+"分"+seconds+"秒";
      document.getElementByIdx_x(time_id[i]).innerHTML=hrsold+"小时"+minsold+"分"+seconds+"秒";
                    }
                }
                
            }
        }
        setTimeout("show_date_time_0()", 100);
    </script>

<div id="TimeCounter_1"></div>
    <script type="text/javascript">
        target[target.length]=new Date(2116,09,28,00,00,00).getTime()
        time_id[time_id.length]="TimeCounter_1"
    </script>