I've a radiobutton list like this;
<asp:RadioButtonList ID="RadioButtonFirm" runat="server" RepeatDirection="Horizontal">
<asp:ListItem id="option1" runat="server" Value="Firm Code" />
<asp:ListItem id="option2" runat="server" Value="Firm Name" />
</asp:RadioButtonList>
and also an asp:button control
<asp:Button ID="btnSearchFirm" runat="server" OnClientClick="Validate();" Text="search" OnClick="btnSearchFirm_Click" />
and a textbox
<asp:TextBox ID="txtCriteria" Width="120px" runat="server"></asp:TextBox>
If I select Firm Code from radio button, user only select numeric value to txtCriteria textbox, else string can be entered. How to validate it?