I was playing around with ASPNET AJAX MaskEditExtender control and ASPNET Validation controls when I was working with a profile page and doing some input validations. Everything seems to be fine until I was told to always retain the phone mask format in the TextBox. Here’s my code for Phone number masking: <asp:TextBox ID="TXTPhoneNumber" runat="server" MaxLength="13" ValidationGroup="GroupA" /> <asp:MaskedEditExtender ID="MaskedEditExtender1" runat="server" TargetControlID="TXTPhoneNu...