用jquery ajax做的select菜单，选中的效果

//用server端语言赋值给js变量

    var departmentId = '<%=提交的值 %>', deviceId='<%=提交的值 %>'

    $(function () {

        $.ajax({

            url: "deJson.action",

            type: 'POST',

            dataType: 'JSON',

            timeout: 5000,

            //error: function() {alert('载入数据异常，请重试!');},

            success: function (data) {

                //$("#departmentId").empty();

                $.each(eval(data), function (i, item) {

                    $("<option value='" + item.id + "'"+(item.id==departmentId?

' selected':'')+">" + item.name + "</option>").appendTo($("#departmentId"));

                });

            }

        });

        $("#departmentId").click(function () {

            loadDevice($("#departmentId").val());

        });



        function loadDevice(departmentId) {

            $.ajax({

                url: 'dJson.action?

departmentId=' + departmentId,

                type: 'POST',

                dataType: 'JSON',

                timeout: 5000,

                error: function () { alert('载入数据异常，请重试!'); },

                success: function (msg) {

                    if (msg == "{[]}") {

                        $("#deviceId").empty();

                        $("<option value='0'>查询全部</option>").appendTo($("#deviceId"));

                    } else {

                        $("#deviceId").empty();

                        $("<option value='0'>查询全部</option>").appendTo($("#deviceId"));

                        $.each(eval(msg), function (i, item) {

                            $("<option value='" + item.deviceId + "'" + (item.id == deviceId ?

' selected' : '') + ">" + item.name + "</option>").appendTo($("#deviceId"));

                        });

                    }

                }

            });

        }

    })

问题描写叙述：

用jquery ajax做的二级联动菜单。联动效果实现了，如今想实现另外一个效果,怎样在表单提交后让刚才选择的下拉菜单项为选中状态？

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