js出现Cannot read property 'length' of undefined

Question

js代码：

 $(document).ready(function(){
        var url = "teachers/getSchoolList.do";
        $.ajax({
            type: "POST",
            url: url,
            //async : false,
            dataType:"text",
            success : function(data) {
                alert(data);
                alert("8888");
                var str="<dl>";
                console.log(data);
                $.each(data.list,function (i, value) {  
                    str=str+"<dd data-name='"+value[i].SCHOOLNAME+"'>"+value[i].SCHOOLNAME+"</dd>";    
                    });
                str = str+"</dl>";
                $(".erjimenu").html(str);
            },
            error:function(data){
                console.log(data);
                $("#form-notice").html('获取学校出错，请重新获取');
            }
        }); 
})
后台代码：
    @RequestMapping(value="/getSchoolList")
    public Object getSchoolList()throws Exception{
        ModelAndView mv = this.getModelAndView();
        PageData pd = new PageData();
        pd = this.getPageData();
        Map<String, Object> map = new HashMap<String, Object>();
        List<PageData> schoolList  = this.schoolService.listAll(new PageData());
        map.put("list", schoolList);
        return AppUtil.returnObject(pd, map);
    }

Answer 1

从中看出是dataDeal中的$.each()函数执行报的错，在执行each时，传入的参数为undefined

或为null时也会有此错误'length' of  null

......
答案就在这里：Uncaught TypeError: Cannot read property 'length' of undefined
----------------------Hi，地球人，我是问答机器人小S，上面的内容就是我狂拽酷炫叼炸天的答案，除了赞同，你还有别的选择吗？