show/hide a div with drop dwon value in asp.net :    its my code i want to hide div which have id selnumber (when i select form 60/61 and show a text message "It is form 60/61" at the place of div) but when select pan then show the div.


    <div id="selpan"> 
                    <asp:DropDownList ID="ddlpan" runat="server">
                        <asp:ListItem>---Select---</asp:ListItem>
                        <asp:ListItem>PAN</asp:ListItem>
                        <asp:ListItem>FORM 60/61</asp:ListItem>
                    </asp:DropDownList> </div>
                    </td><div id="selnumber">
                    <td colspan="3">&nbsp;&nbsp;&nbsp;&nbsp; 
                    <asp:Label ID="add_no" runat="server" Font-Bold="True" Font-Names="Verdana" 
                            Font-Size="10pt" Font-Strikeout="False" Text="File Number"></asp:Label>
                       </td><td> 
                    <asp:TextBox ID="tbnumber" runat="server" ontextchanged="tbnumber_TextChanged"></asp:TextBox>
                    </td>
                    </div>