(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);