前台代码：

    <script src="js/jquery.js" type="text/javascript"></script>    

<script type="text/javascript">        

function showAll() {            

$.get("Default2.aspx?select=yes", function (data) {               

  var json = eval(data);               

  var html = "<table border=1 bordercolor=red cellspacing=1>";               

  html += "<tr bgcolor='yellow'><td>客户ID</td><td>客户类型</td><td>用户ID</td></tr>";             

    for (var i = 0; i < json.length; i++) {                                                           html += "<tr>";

                    html += "<td>" + json[i].Comp_companyid + "</td><td>" + json[i].Comp_type + "</td><td>" +json[i].User_userid + "</td>";                

     html += "</tr>";        

         }              

   html += "</table>";               

  $("#nihao").html(html);      

       });            

     }    

</script>

后台：

 protected void Page_Load(object sender, EventArgs e)
    {
        Response.Cache.SetCacheability(HttpCacheability.NoCache);
        if (Request.QueryString["select"] != null)
        {
            List<Comany> list = ComanyBLL.GetAllComany();
            string str = Newtonsoft.Json.JsonConvert.SerializeObject(list);
            Response.Write(str);
            Response.End();
        }
    }