javascript countdown clock

Answer 1

I've cleaned up the above code and made it format like your example. It also removed the global variables and allows you to create multiple timers.

There's a live link here http://jsfiddle.net/Apnu2/6/

countdown('countdown', 1, 5);
function countdown(element, minutes, seconds) {
    // set time for the particular countdown
    var time = minutes*60 + seconds;
    var interval = setInterval(function() {
        var el = document.getElementById(element);
        // if the time is 0 then end the counter
        if(time == 0) {
            el.innerHTML = "countdown's over!";    
            clearInterval(interval);
            return;
        }
        var minutes = Math.floor( time / 60 );
        if (minutes < 10) minutes = "0" + minutes;
        var seconds = time % 60;
        if (seconds < 10) seconds = "0" + seconds; 
        var text = minutes + ':' + seconds;
        el.innerHTML = text;
        time--;
    }, 1000);
}