Javascript count down timer in a MYSQL column

http://dev.mysql.com/doc/refman/5.5/en/date-and-time-functions.html#function_timediff

You wouldn't store the countdown column directly. Instead you would use timediff.

So something like

select timediff(now(), end_time) from countdown_table

I think you are mixing up server-side and client-side although I'm not completely sure what you are trying to do.

You don't need any timers in your database, you just need the end-time. In your php script you can then get the current time (or in MySQL...) and the end-time and initialize your javascript timer with the difference between the two so that the timer can count down in the visitor's browser.

Just an FYI, you can write a counter purely in javascript on the client. If you want to countdown to a specific time in the future that's stored in a mysql database you can still use Javascript and do something like this in your PHP page:

<script>
var endTime = <?= $endTimeFromDb; ?>; // preferably a unix timestamp in ms
var relativeTime = new Date().getTime() - endTime; // relative ms until endTime
// now apply some fancy formatting and write it to the dom
</script>

Then you can use something like TimeSpan.js to convert your relativeTime into a pretty format: https://github.com/idottv/TimeSpan.js

See the MDN for more information about the JavaScript Date Object: https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Date

After Looking more careful at the plugin you want to you use I came up with this

var endTime = <?= $endTimeFromDb; ?>; // if it's a timestamp
var endTime = "<?= $endTimeFromDb; ?>"; // if it's a string
$("div.countdown").countdown({until: new Date(endTime)});

Let me know if neither of those examples made any sense.