totalSeconds = 600;
    seconds = 600;

    function updateCountdown() {
        seconds = seconds - 1;

        minutes = Math.floor(seconds/60);
        secondsDisplay = seconds - (((minutes))* 60);
        if(secondsDisplay > 59) {
            secondsDisplay = 59;
        }
        else if(secondsDisplay < 0) {
            secondsDisplay = 0;
        }

        if(secondsDisplay.toString().length == 1) {
            secondsDisplay = '0' + secondsDisplay.toString();
        }

        if(minutes == 0 && secondsDisplay == 0) {
            document.getElementById('countdown').innerHTML = 'Time is up!';
        }
        else {
            document.getElementById('countdown').innerHTML = minutes+":"+secondsDisplay+" remaining";
            //document.getElementById('countdown').innerHTML = minutes+" minutes and "+secondsDisplay+" seconds remaining";
            setTimeout("updateCountdown()",1000)
        }
    }