อยาก sort ข้อมูลจาก XMLด้วยjava script พอดีต้องแก้โปรเจค aspx

 function OnSuccess(response) {
            var xmlDoc = $.parseXML(response.d);
            var xml = $(xmlDoc);
            pageCount = parseInt(xml.find("PageCount").eq(0).find("PageCount").text());
            var items = xml.find("fnn_product");

            items.sort(function () {
                return $items.find("productname") - $items.find("productname");
            });
            items.each(function () {
                var item = $(this);
               
                var str = '';

                str = "<div class='" + item.find("class").text() + "'>";
                str += "  <div class='pc_img'><img src='" + item.find("thumb").text() + "'/></div>";
                str += "  <div class='pc_head'>" + item.find("productname").text() + "</div>";
                str += "  <div class='pc_detail'>" + item.find("productdetail").text() + "</div>";
                str += "</div>";
                

                $("#divContent").append(str);
            });