Hello,
I recently (yesterday) completed a project involving a countdown. I don't know exactly what you will do with this countdown. Who will use it? If the user enters a date / hour in a form, he has to stay there for a week to see it countdown to 30 seconds...
So you need a system where this info is displayed on the user's site? Or on your site, but the script needs to remember the countdown?
fireworks can be made with flash or html5