how to handle dropdownlist mvc/jquery

i´m new developing on asp.net mvc, and even newer using jquery, so this is my problem: i have a few dropdown list that are filled dinamically using the data of another dropdown or textbox, and the data of those drop down is used for another drop down, like a chain, my problem rigth now is that the dropdown sometimes just have one answer/option, and if i try to select that option jquery doesn´t activate the $("#anything").change() event, 'cause i have just one option, how i handle it?

http://imageshack.us/photo/my-images/20/sinttulolp.jpg/

for example this i need the data of the red circle for filling the blue circle, but the red circle just have one option and if i click nothing happens

code:

$("#tbClave1").change(function() {
	                if ($("#tbClave1").val().length == 4) {
	                    updateClave2($("#tbClave1").val());
	                }
	            });


function updateClave2(cod) {

                var dd = document.getElementById("ddClave2");
                dd.options.length = 0;
                dd.options[0] = new Option("Espere...");
                dd.selectedIndex = 0;
                dd.disabled = true;
                codigo = cod;
                tipoArt = $("#ddTipoArticulo").val();
                // Control de errores
                $("#ddClave2").ajaxError(function(event, request, settings) {
                    dd.options[0] = new Option("No se Cargaron Datos");
                });
                // Obtenemos los datos...
                $.ajax({
                    url: '/Home/GetClave2',
                    dataType: 'json',
                    data: { words: codigo, tipoArticulo: tipoArt },
                    success: function(data, textStatus, jqXHR) {
                        $.each(data, function(i, item) {
                            dd.options[i] = new Option(item["clave2"], item["clave2"]);
                        });
                        dd.disabled = false;
                    }
                });
            }


controller:

public ActionResult GetClave2(string words, string tipoArticulo){
             List<Pedidos> mySource = miConexion.Clave2(username, password, words, tipoArticulo);
             return Json(mySource);
         }

connection:

public List<Pedidos> Clave2(string username, string password,
                                            string clave1, string tipoArticulo)
        {
            List<Pedidos> clave2 = new List<Pedidos>();
            try
            {
                OleDbConnection conexion = new OleDbConnection
                    (@"....");

                OleDbCommand comandoSelect = new OleDbCommand(@" sql sentence " , conexion);
                
                 comandoSelect.Connection = conexion;
                 conexion.Open();
                 comandoSelect.ExecuteNonQuery();
                 OleDbDataReader resultado = comandoSelect.ExecuteReader();
                
                 while (resultado.Read()){
                     Pedidos miClave2 = new Pedidos();
                     miClave2.clave2 = resultado.GetString(0);
                     clave2.Add(miClave2);
                 }
                 conexion.Close();
            }
            catch (Exception ex)
            {
                System.Diagnostics.Debug.WriteLine(ex.Message);
            }
            return clave2;
        }

Re: how to handle dropdownlist mvc/jquery

check this cascading dropdown list

http://www.c-sharpcorner.com/uploadfile/2124ae/cascading-dropdown-list-in-Asp-Net-mvc-2-using-jquery/

Re: how to handle dropdownlist mvc/jquery

but i initialize, and fill it different ... how i add that first value to the dropdown, and then start fill it in the next position?

i forgot tell u that i use mvc v1

How i initialize:

ViewData["ddClave2"] = new SelectList(new[] { "(Selecciona)" });

how i deffine it:

<% =Html.DropDownList("ddClave2") %>