asp.net中添加数据ajax读取不到新数据，请高手指教

--插入数据方法
       
        function insertUser()
        {
            $.get("inseruser.ashx",{uname:$("#uname").val(),upwd:$("#upwd").val(),uage:$("#uage").val(),usex:$("#usex").val()},function(msg){
            $("#aaa").text(msg);
             getdata3();
            });
            
          
        }
        
---得到所有信息方法 
function getdata3()
        {
                
           
                $.getJSON(
                "UserAllHandler.ashx",
            
                    function(data){
                  
                    var table=$("<table align=center width=60% border=1>"+
                    "<tr>"+
                    "<td>编号</td>"+
                    "<td>姓名</td>"+
                    "<td>年龄</td>"+
                    "<td>密码</td>"+
                    "</tr></table>");
                  
                    var user=data;
                    //document.write(user.length);
                    for(var i=0;i<user.length-1;i++)
                    {
                        $("table").empty();
                         u=user[i];
                         var row=$("<tr></tr>");
                         //document.write(key);
                         
                           var td0=$("<td></td>");
                             td0.text(i+1);
                       
                            var td1=$("<td></td>");
                             td1.text(u.uname);
                            var td2=$("<td></td>");
                              td2.text(u.upwd);
                            var td3=$("<td></td>");
                            td3.text(u.uage);
                            
                             td0.appendTo(row);
                            td1.appendTo(row);
                            td2.appendTo(row);
                            td3.appendTo(row);
                            
                        
                        row.appendTo(table);
                        
                        
                    }
                    table.appendTo($("#dd"));
                },"json");
              
        } 
------------UserAllHandler.ashx文件
<%@ WebHandler Language="C#" Class="UserAllHandler" %>using System;
using System.Web;
using System.Data;
using System.Text;public class UserAllHandler : IHttpHandler {
    Users user = new Users();
    DataSet ds = new DataSet();
    public void ProcessRequest (HttpContext context) {
        context.Response.ContentType = "text/plain";
        //context.Response.Write("Hello World");
        
        context.Response.Clear();
        
        this.ds = user.userSelectAll();
        StringBuilder sb = new StringBuilder();
        //sb.Append("[");
        sb.Append("[");
        for (int i = 0; i < this.ds.Tables[0].Rows.Count; i++)
        {
            string uname = this.ds.Tables[0].Rows[i]["uname"].ToString();
            string upwd = this.ds.Tables[0].Rows[i]["upwd"].ToString();
            string uage = this.ds.Tables[0].Rows[i]["uage"].ToString();           // sb.Append("{\"uname\":\"mike\",\"upwd\":\"123bac\",\"uage\":29},");
            sb.Append("{\"uname\":\"" + uname + "\",\"upwd\":\"" + upwd + "\",\"uage\":\"" + uage + "\"},");        }
        sb.Append("]");
        context.Response.Flush();
        context.Response.Write(sb);
        context.Response.End();
    }
 
    public bool IsReusable {
        get {
            return false;
        }
    }--插入数据调用insertUser()
后，调用 getdata3()看不到新的数据。
请高手指教。在线等侯谢谢