var interval;
    var minutes = 3;
    var seconds = 5;
	
    window.onload = function() {
        countdown('countdown');
    }

    function countdown(element) {
        interval = setInterval(function() {
            var el = document.getElementById(element);
            if(seconds == 0) {
                if(minutes == 0) {
                    el.innerHTML = "Starter nu!";                    
                    clearInterval(interval);
                    return;
                } else {
                    minutes--;
                    seconds = 60;
                }
            }
            if(minutes > 0) {
                var minute_text = minutes + (minutes > 1 ? ' minutter' : ' minut');
            } else {
                var minute_text = '';
            }
            var second_text = seconds > 1 ? 'sekunder' : 'sekund';
            el.innerHTML = minute_text + ' ' + seconds + ' ' + second_text + ' tilbage';
            seconds--;
        }, 1000);
    }