var rotatorIntervalId;
    function showNextItem(clickedButton, rotator, direction, auto) 
    {
        if (auto) {
            rotator.showNext(direction);
            rotatorIntervalId = window.setInterval(function() { rotator.showNext(direction) }, 250);
        }
        else {
            window.clearInterval(rotatorIntervalId);
            rotatorIntervalId = 0;
        }
        return false;
    }