ajax加载数据字典下拉选后台

<script type="text/javascript" src="${pageContext.request.contextPath }/js/jquery-1.4.4.min.js"></script>
<script type="text/javascript">

//使用ajax加载数据字典,生成select
//参数1: 数据字典类型 (dict_type_code)
//参数2: 将下啦选放入的标签id
//参数3: 生成下拉选时,select标签的name属性值,也就是下拉选的标题字段，哪个下拉
//参数4: 需要回显时,选中哪个option
    function loadSelect(typecode,positionId,selectname,selectedId){
        //1 创建select对象,将name属性指定
        var $select = $("<select name="+selectname+"></select>");
        //2 添加提示选项
        $select.append($("<option value=''>--- 请选择 ---</option>"));
        //3 使用jquery 的ajax 方法,访问后台Action
        $.post("${pageContext.request.contextPath}/BaseDictAction",{dict_type_code:typecode},
            function(data){
            //4 返回json数组对象,对其遍历
                $.each(data, function(i, n){
                    //每次遍历创建一个option对象 
                    var $option = $("<option value='"+n['dict_id']+"'>"+n["dict_item_name"]+"</option>");
                    if(n["dict_id"]==selectedId){
                        //判断是否需要回显 ,如果需要使其被选中
                        $option.attr("selected","selected");}
                    //并添加到select对象
                    $select.append($option);
                });    
        },"json");
        //5 将组装好的select对象放入页面指定位置
        $("#"+positionId).append($select);
    }
    
    $(document).ready(function(){
        
        loadSelect("006","level","cust_level.dict_id","a");
        loadSelect("001","industry","cust_industry.dict_id","a");
        loadSelect("002","source","cust_source.dict_id","a"); 
        
        });