Caveman time formatting in Javascript

caveman_time.js

function formatTime( seconds ) {
	seconds = Math.round( seconds );
    var hours = 0,
    	minutes = 0;
    while (seconds >= 3600) {
      hours += 1;
      seconds -= 3600;
    }
    while (seconds >= 60) {
      minutes += 1;
      seconds -= 60;
    }
	if ( hours > 0) {
		return hours + ':' + (minutes < 10 ? '0' : '') + minutes + ':' + (seconds < 10 ? '0' : '') + seconds;
	} else {
		return minutes + ':' + (seconds < 10 ? '0' : '') + seconds;
	}
}