UL subdrop not working with jquery in Asp Net C

Question

Keep searching why sub drop not working with ajax.. Menu is showing but when i click the menu the sub menu is was not displaying.

            $.ajax({
                url: '../url',
                dataType: "json",
                data: { data},
                method: 'post',
                success: function (data) {
                    var html, ul_menu = ''
                    ul_menu = $('#ul-menu');
                    $(data).each(function (index, menu) {
                        html = ''
                            + '<li class="has_sub">'
                                + '<a href="javascript:void(0);" class="waves-effect"><i class="mdi mdi-album"></i> <span> Menu </span> <span class="float-right"><i class="mdi mdi-plus"></i></span></a>'
                                + '<ul class="list-unstyled">'
                                    + '<li><a href="index.html?sys=hris&mod=human-resource&sub=man-power-request">Sub Menu 1</a></li>'
                                    + '<li><a href="ui-components.html">Sub Menu 2</a></li>'
                                + '</ul>'
                            + '</li>';
                        ul_menu.append(html);
                    });
                }
            });

Please help Thanks