Try to use Ajax markededitor extender for this.
eg :
< asp:TextBox ID = "TextBox1" runat = "server" ForeColor = "HotPink" >
< cc1:MaskedEditExtender ID = "MaskedEditExtender1" runat = "server" TargetControlID = "TextBox1" Mask = "9999-9999-99-9999999999" MaskType = "Number" MessageValidatorTip = "true" >