Countdown Clock
<p>I would like to create a countdown clock that when  you show up on the page it starts to countdown from a pre-defined number, say 8 hours. If you leave the page, say after 2 hours, I would like it to stop counting down. If you return to the page I want it to resume counting down, now with only 6 hours left.</p>

<p>Is this possible using javascript client side, and php server side?</p>

<p>If I wanted to create multiple user generated countdowns can I use mySQL to store the different variables?</p>

<p>Obviously I have a lot to work out here, I don't want someone to write me the whole code. I am looking for a starting point, maybe some tutorials or advice on which way to start perusing. I am very much a novice at js, php, mysql but can work with them.</p>
