$(function () {
    var jumpnavcount = $(".jumpnav dt").size();
    $(".htxt").each(function (index, element) {
        if (jumpnavcount > 0)
        {
            var obj = $(this);
            var a = obj.find("a");
            var top = obj.offset().top;
            var height = obj.innerheight()
            top = top - height;
            var text = obj.find("h3").text();
            obj.append("<h4>" + text + "</h4>");
            var h4 = obj.find("h4")
            h4.css("left", (obj.width() - h4.width()) / 2)
            h4.show();
            a.css("visibility", "hidden");
            var cango = obj.data("cango",true);
            var hasgo = obj.data("hasgo", false);

        
            $(window).scroll(function () {
                if ($(window).scrolltop() > top + 150 && $(window).scrolltop() < top + height+100) {
                    if (obj.data("cango")) {
                        obj.data("cango", false);
                        $(".htxt").eq(index-1).find("h4").stop(true, true).hide();
                        $(".htxt").eq(index - 1).find("a").css("visibility", "visible");
                        settimeout(function () {
                            h4.animate({ left: 0, top: a.position().top, fontsize: "35px" }, 500, function () {
                                h4.hide()
                                a.css("visibility", "visible");
                                obj.data("hasgo", true);
                            });
                        }, 300);
                    }
                }
                else if ($(window).scrolltop() < top &&  obj.data("hasgo")) {
                    obj.data("hasgo", false);
                    obj.data("cango", true);
                    h4.stop(true, false).css("left", (obj.width() - h4.width()) / 2).css("top", 0).css("font-size", "55px");
                    h4.show();
                    a.css("visibility", "hidden");

                }
            });

        }
    });

})