$(window).on("load scroll", function() {
    if ($(".history-list").length) {
        var el = $(".history-list"),
            item = el.find("> ul > li"),
            t = $(this),
            scrTop = t.scrollTop() + (t.height() / 1.75),
            scrTopE = t.scrollTop() + (t.height() / 1.8),
            conTop = el.offset().top,
            conH = el.height(),
            prog = $(".progress"),
            itemPos = new Array,
            itemH = new Array;
        item.each(function(index) {
            var t = $(this);
            itemPos.push(t.offset().top);
            itemH.push(t.outerHeight());
            var per = Math.floor((scrTop - conTop) / (conH) * 100);
            if (per <= 95) {
                prog.css("height", per + "%");
            } else if (per > 96) {
                prog.css("height", 100 + "%");
            } else if (per < 10) {
                prog.css("height", 0 + "%");
            }
            if (scrTopE >= itemPos[index]) {
                t.addClass("effect");
            } else {
                t.removeClass("effect");
            }
        });
    }

});