[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!