jquery替文本框赋值后 后台取不到值

jquery为文本框赋值后 后台取不到值?
 <asp:Label ID="lkb1" Class="lkb1" name="name" runat="server" Text="挺进投资产品A"></asp:Label>
      <asp:TextBox ID="TextBox1" name="TextBox1"  ReadOnly="True"   runat="server" Text=""></asp:TextBox>  
                                        
                   <script>
                       var curId; // 保存全局id
                       $(document).mousemove(function (e) {
                           {
                               e = e || event;
                               var tag = e.srcElement || e.target;
                               if (tag.id) {
                                   curId = tag.id;
                                   
                                   var dd = $("." + curId + "")();
                                  $("#TextBox1").val("" + dd + "");//赋值  
                               }
                           }
                       });
                      
                       </script>
////上面鼠标移动事件能赋值给TextBox1
////现在问题是我后台取不到值
////去掉ReadOnly="True"..也取不到值
///跪求高手解决
 string str = Request.Form["TextBox1"];
 string tbox = this.TextBox1.Text;