var ResultArray = new Array();
        ResultArray.push({ id: "Name", value: $("#fio_name").val() });
        ResultArray.push({ id: "Adress", value: $("#adress").val() });

        ...
        итд

        var string_to_server = JSON.stringify(ResultArray);

            $.ajax(
                {
                    url: 'http://127.0.0.1:81/jud/save_user_common_data_jsonp?callback=?',
                    success: function (result) {

                           //...........

                    },
                    data: {
                        'user_info_and_users_cars_1_only_user_info_2': 2
                        , 'sp_code_new_qty': JSON.stringify(ResultArray)
                    },
                    dataType: 'json',
                    timeout: 100000,
                    error: function (result) { alert('Ошибка соединения с сервером'); }
                });

  <system.web.extensions>
    <scripting>
      <webServices>
        <jsonSerialization maxJsonLength="стотыщмильёнов"></jsonSerialization>
      </webServices>
    </scripting>
  </system.web.extensions>

    } catch (e) {
        alert("Ошибка: " + e.name + ": " + e.message);
    }