(function ($) { //瓒呰繃涓€瀹氶珮搴﹀鑸坊鍔犵被鍚 var nav = $(".c_portalResnav_main-01001005 .header1"); //寰楀埌瀵艰埅瀵硅薄 var win = $(window); //寰楀埌绐楀彛瀵硅薄 var sc = $(document); //寰楀埌document鏂囨。瀵硅薄銆 if (sc.scrollTop() >= 50) { nav.addClass("active"); } else { nav.removeClass("active"); } })(jQuery);