(function() {
    var timer;
    var startScrolling = function() {
        timer = setInterval(scrollOnce, 1000);
    };
    var stopScrolling = function() {
        clearInterval(timer);
    };
    var scrollOnce = function() {
        var moveBy = Math.max($('#slideshow-navigation').css('left'), 0);

        $('#slideshow-navigation').animate({ left: '-=' + moveBy }, 700);
    };
    $('#arrowlink').hover(startScrolling, stopScrolling);
})();