airbnb's nifty search scrolling uses onscroll event

airbnb.js

        var m, j;
        var l = jQuery("#search_filters");
        var c = jQuery("#search_body");
        var p = l.position().top;
        var k = l.height();

        function n() {
            var s = jQuery(window).scrollTop();
            var r = l.position().top;
            if ((s >= p) && (k < j)) {
                if (!l.hasClass("fixed")) {
                    l.addClass("fixed")
                }
                if (((k + r) >= m) && s >= r) {
                    l.css({
                        position: "absolute",
                        top: m - k + 1 + "px"
                    })
                } else {
                    if (l.css("position") === "absolute") {
                        l.css({
                            position: "",
                            top: "0"
                        })
                    }
                }
            } else {
                d()
            }
        }
        function d() {
            if (l.hasClass("fixed")) {
                l.removeClass("fixed")
            }
            if (l.css("position") === "absolute") {
                l.css({
                    position: "",
                    top: "0"
                })
            }
        }
        function f() {
            k = l.height();
            n();
            n()
        }
        AirbnbSearch.$.bind("finishedrendering", function () {
            p = c.position().top;
            k = l.height();
            j = c.height();
            m = p + j;
            if ((j > k) && AirbnbSearch.currentViewType !== "map") {
                jQuery(window).scroll(n).scroll();
                AirbnbSearch.$.bind("filtertoggle", f)
            } else {
                jQuery(window).unbind("scroll", n);
                AirbnbSearch.$.unbind("filtertoggle", f);
                d()
            }
        });