Menüpunkt der aktuellen Seite hervorheben

$(document).ready(function () { var positions = [];
                $("#nav a").each(function () {
                    var anchr = $(this).attr("href");
                    var entry = { anchor: anchr, pos: $(anchr).offset().top };
                    positions.push(entry);
                });
                function highlightnav() {
                    var currentPos = $(window).scrollTop();
                    var idx = 0, anchr;
                    for (var i = 0; i < positions.length; i++) {
                        if (positions[i].pos < currentPos) idx = i;
                    }
                    anchr = positions[idx].anchor;
                    $("#nav a").each(function () {
                        if ($(this).attr("href") == anchr) {
                            $(this).addClass("current");
                        } else {
                            $(this).removeClass("current");
                        };
                    });
                }
                $(window).on("scroll", highlightnav)                             });