jQuery Load form elements through ajax, from onchange event of drop down box

Answer 1

Following code gets the data via ajax call for OnChange Event and fills another DropDown

    $("#IdOfyourDropDown").change(function () {

      $.getJSON('<%= ResolveUrl("~/PutYourURL/?Id="1)%>', function (data) 
            {
                    Result = data; //Use this data for further creation of your elements.
                     var items = "";
                    items += " -- ";
                    $.each(data, function (i, SingleElement) {
                        items += "" + SingleElement.Text + "";
                    });
                    $("#AnyOtherDropDown").html(items);

            });
     });

I used getJSON to retrieve the data, you can use many more