淘宝网倒计时脚本JS最新版解析与使用

JS:淘宝网的剩余时间（倒计时）是怎么做的？ 

这时淘宝网上的源代码    
  <SCRIPT   language=JavaScript>    
  var   auctionDate   =   120;    
  var   startTime   =   (new   Date()).getTime();    
  var   Temp;    
  var   timerID   =   null;    
  var   timerRunning   =   false;    
  function   showtime()    
  {    
          now   =   new   Date();    
          var   ts=parseInt((startTime-now.getTime())/1000)+auctionDate;    
          var   dateLeft   =   0;    
          var   hourLeft   =   0;    
          var   minuteLeft   =   0;    
          var   secondLeft   =   0;    
          if(ts   <   0)    
          {    
                  ts   =   0;    
                  CurHour   =   0;    
                  CurMinute   =   0;    
                  CurSecond   =   0;    
          }   else   {    
                  dateLeft   =parseInt(ts/86400);    
                  ts   =   ts   -   dateLeft   *   86400;    
                  hourLeft   =   parseInt(ts/3600);    
                  ts   =   ts   -   hourLeft   *   3600;    
                  minuteLeft   =   parseInt(ts/60);    
                  secondLeft   =   ts   -   minuteLeft   *   60;