<asp:DropDownList ID="list_localita" runat="server" Width="250px"></asp:DropDownList>
 <cc1:CascadingDropDown ID="cdllocalita" TargetControlID="list_localita" PromptText="Seleziona località" PromptValue="" ServicePath="WebService.asmx" ServiceMethod="GetCountries" runat="server" Category="Codice" LoadingText="Caricamento..." />