Not sure if this info is correct, but, if my memory serves me correctly, I BELIEVE Alex Albert (who is a fellow warrior) had created a script a while back that did exactly what you want/need.

I tried searching Google and couldn't find the product, but I know he had released something very similar a while back.

If I am incorrect, I sincerely apologize, but I am almost positive it was his release I am thinking of.

HTH.

There are plenty of javascript countdown timers available free around the internet.

Just type in google "free javascript countdown timer" You will find one in minutes. No pun intended.