JS Countdown Refresh?

[Sparktastic]

What can I add to my code to refresh the timer's output?

here's my Script:

<script language="javascript" type="text/javascript">

today  = new Date();
todayEpoch  = today.getTime();

target = new Date("03 May, 2012"); 
targetEpoch = target.getTime();

daysLeft = Math.floor(((targetEpoch - todayEpoch) / (60*60*24)) / 1000);
hoursLeft = Math.floor(((targetEpoch - todayEpoch) / (60*60)) /1000);
minutesLeft = Math.floor(((targetEpoch - todayEpoch) / (60)) /1000);
secondsLeft = Math.floor(((targetEpoch - todayEpoch)) /1000);

hours = Math.floor((hoursLeft)-((daysLeft)*24)); 
minutes = Math.floor((minutesLeft)-(hoursLeft*60));
seconds = Math.floor((secondsLeft)-(minutesLeft*60));
</script>

and how it would be placed in a html document (snippet):

I  am 18 in: <br>
<script>document.write(daysLeft);</script> Days, <br>
<script>document.write(hours);</script> Hours, <br>
<script>document.write(minutes);</script> Minutes and <br>
<script>document.write(seconds);</script> seconds! <br>

Any help appreciated!

[felgall]

To have the countodwn update within the page you need to throw away all that antiquated JavaScript and start again.

document.write can only run before the page loads and is only useful where you don't have access to generate the output on the server.

See http://javascript.about.com/library/blcount1.htm for the sort of code you need to be able to have the countdown timer actually count down.