Asp/asp.net中下拉列表的N级联动

 <form runat="server">
  州
    <asp:DropDownList ID="DDListCountry" runat="server">  </asp:DropDownList>
    国
    <asp:DropDownList ID="DDListProvince" runat="server"></asp:DropDownList>
    省
    <asp:DropDownList ID="DDListCity" runat="server"></asp:DropDownList>
    市
    <asp:DropDownList ID="DDListVillage" runat="server"></asp:DropDownList>
  
</form>


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