Validate Integer (Number) and Float (Decimal) values in ASP.Net TextBox

Make use of AJAX MaskEditExtender

<asp:TextBox ID="txtAmount" runat="server" />
                    <cc1:MaskedEditExtender ID="MaskedEditExtender1" runat="server" TargetControlID="txtAmount"
                        Mask="9{9}.99" MaskType="Number" InputDirection="RightToLeft" />