i.event.bind(i.scrollbarYRail, 'click', function (e) {
    var positionTop = e.pageY - window.pageYOffset - pageOffset(i.scrollbarYRail).top;
    var direction = positionTop > i.scrollbarYTop ? 1 : -1;

    updateScroll(element, 'top', element.scrollTop + direction * i.containerHeight);