function countdown_clock(year, month, day, hour, minute, format)
{
//I chose a div as the container for the timer, but
//it can be an input tag inside a form, or anything
//who's displayed content can be changed through
//client-side scripting.
html_code='<div id="countdown"></div>';
         
document.write(html_code);
         
Today=new Date();
Todays_Year=Today.getYear() - 2000;
Todays_Month=Today.getMonth() + 1;
         
//Computes the time difference between the client computer and the server.
Server_Date=(new Date(24, 9, 8,
8, 5, 12)).getTime();
Todays_Date=(new Date(Todays_Year, Todays_Month, Today.getDate(),
   Today.getHours(), Today.getMinutes(), Today.getSeconds())).getTime();
countdown(year, month, day, hour, minute, (Todays_Date - Server_Date), format);                
}
         
function countdown(year, month, day, hour, minute, time_difference, format)
{
Today=new Date();
Todays_Year=Today.getYear() - 2000;
Todays_Month=Today.getMonth() + 1;
                                             
//Convert today's date and the target date into miliseconds.
         
Todays_Date=(new Date(Todays_Year, Todays_Month, Today.getDate(),
                                 Today.getHours(), Today.getMinutes(), Today.getSeconds())).getTime();
Target_Date=(new Date(year, month, day, hour, minute, 00)).getTime();
         
//Find their difference, and convert that into seconds.
//Taking into account the time differential between the client computer and the server.
Time_Left=Math.round((Target_Date - Todays_Date + time_difference) / 1000);
if (Time_Left < 0) Time_Left=0;
switch (format)
   {
   case 0: //The simplest way to display the time left.
   document.all.countdown.innerHTML=Time_Left + ' seconds';
   break;
   case 1: //More datailed.
   days=Math.floor(Time_Left / (60 * 60 * 24));
   Time_Left %= (60 * 60 * 24);
   hours=Math.floor(Time_Left / (60 * 60));
   Time_Left %= (60 * 60);
   minutes=Math.floor(Time_Left / 60);
   Time_Left %= 60;
   seconds=Time_Left;
   dps='s'; hps='s'; mps='s'; sps='s';
   //ps is short for plural suffix.
   if (days == 1) dps ='';
   if (hours == 1) hps ='';
   if (minutes == 1) mps ='';
   if (seconds == 1) sps ='';
  
   //document.all.countdown.innerHTML=days + ' day' + dps + ' ';
   //document.all.countdown.innerHTML += hours + ' hour' + hps + ' ';
   //document.all.countdown.innerHTML += minutes + ' minute' + mps + ' and ';
   //document.all.countdown.innerHTML += seconds + ' second' + sps;
   document.all.countdown.innerHTML=days + 'd ';
   document.all.countdown.innerHTML+=hours +'hr'+hps+' ';
   document.all.countdown.innerHTML += minutes + 'min ';
   document.all.countdown.innerHTML += seconds + 'sec';
   break;
   default: 
   document.all.countdown.innerHTML=Time_Left + ' seconds';
   }
       
//Recursive call, keeps the clock ticking.
setTimeout('countdown(' + year + ',' + month + ',' + day + ',' + hour + ',' + minute + ',' + 
             time_difference + ', ' + format + ');', 1000);
}