紧急求助，JQuery UI做成动态outlook菜单为什么不折叠起来？

通过Menu.asmx/ReturnMenu返回菜单Json对象是：

[{"id":"1","pid":null,"cname":"第1级菜单"},
{"id":"2","pid":null,"cname":"第2级菜单"},
{"id":"3","pid":null,"cname":"第3级菜单"},
{"id":"4","pid":"1","cname":"第1级子菜单一"},
{"id":"5","pid":"2","cname":"第2级子菜单一"},
{"id":"6","pid":"3","cname":"第3级子菜单一"},
{"id":"7","pid":"3","cname":"第3级子菜单二"},
{"id":"8","pid":"3","cname":"第3级子菜单三"}]

--javascript代码如下----------------------------------------------------------

<script type="text/javascript">
        $(function () {
            $.ajax({
                type: "POST",
                url: "Menu.asmx/ReturnMenu",
                contentType: "application/json; charset=utf-8",
                dataType: "json",
                success: function (data, status) {
                    var jsonObj = eval("(" + data.d + ")");
                    //---------------------------------
                    objArr = jsonObj;
                    var html = "";
                    $.each(objArr, function (i, obj) {
                        if (obj.pid == null) {
                            //html = html + "<h3><a href=\"#\">" + obj.displayText + "</a></h3>";
                            html = html + "<h3><a href='#'>" + obj.displayText + "</a></h3>";

                            html = html + "<div><ul>";
                            $.each(objArr, function (x, obj2) {
                                if (obj2.pid == obj.id) {
                                    html = html + "<li class='first_level' onclick=''><a href='#'>" + obj2.displayText + "</a> </li>";
                                }
                            });
                            html = html + "</ul></div>";

                        }
                    });

                    $("#accordion").append(html);
                    $("#accordion").accordion();

                },
                error: function () {
                    alert("error");
                }
            });
        });
    </script>

--html代码如下----------------------------------------------------------

<body>
<div id="accordion"> </div>
</body>

JQuery JQuery accordion --------------------编程问答-------------------- 默认是展开的吧。。你看看是不是有什么事件  主动隐藏

补充：.NET技术 ,  ASP.NET