Question

Possible Duplicate:
How to create a JQuery Clock / Timer

Does anyone knows countdown timer using javascript??

Answer 1

Using pure javascript, you would use the setTimeout method in a manner similar to this (treat this code as pseudocode, it is just to show the concept, I do not think it will work as-is):

countdown = function()
{
   var current = parseInt(document.getElementById("countdownBox").innerHTML);
   document.getElementById("countdownSpan").innerHTML = current;

   if (current > 0)
   {
       setTimeout('countdown()', 1000); // run every second
   }
}

You would start the countdown by writing something in the element with id countdownBox and calling countdown() for the first time.

Edit: note that the setTimeout method will tend to lose seconds if used this way – if you want real precision you will most likely have to synchronize externally every once in a while.