var secs;
var timerID = null;
var timerRunning = false;
var delay = 1000;

function InitializeTimer()
{
    // Set the length of the timer, in seconds
    secs = 5;
    StopTheClock();
    StartTheTimer();
}

function StopTheClock()
{
    if(timerRunning)
        clearTimeout(timerID);
    timerRunning = false;
}

function StartTheTimer()
{
    if (secs==0)
    {
        StopTheClock();
        // Here's where you put something useful that's
        // supposed to happen after the allotted time.
		setOverlay(false);
    }
    else
    {
        self.status = secs;
        secs = secs - 1;
        timerRunning = true;
        timerID = self.setTimeout("StartTheTimer()", delay);
    }
}