Js custom scroll

var scrolled = window.pageYOffset || document.documentElement.scrollTop,
                container = $('.up-block-left-sections-details');


            container.bind('mousewheel', function(e) {
                var booksTreeHeight = $(".books-tree.info-books").height();
                if(container.height() > booksTreeHeight + 60 || !container.hasClass("fixed")) return;
                var height = container.height();
                var scrollHeight = container[0].scrollHeight;
                var st = container.scrollTop();
                var delta = e.originalEvent.wheelDelta < 0 ? true : false;

                if((st >= scrollHeight - height - 5 && delta) || st == 0  && !delta) {
                    e.preventDefault();
                }
                else{
                    delta = 0;
                    if (e.originalEvent.wheelDelta) delta = e.originalEvent.wheelDelta / 120;
                    else if (e.originalEvent.detail) delta = -e.originalEvent.detail / 3;
                    handle(delta);
                    if (e.preventDefault) e.preventDefault();
                    e.originalEvent.returnValue = false;
                }

                function handle(delta) {
                    var time = 1000;
                    var distance = 180;

                    container.stop().animate({
                        scrollTop: $(window).scrollTop() - (distance * delta)
                    }, time );
                }