hi,

you have to use a javascript method for custom validation on aspx page not the servervalidate event of custom validator

example

<SCRIPT LANGUAGE="JavaScript"> function validatefunction(oSrc, args){ //logic for odd number

} </SCRIPT> <asp:Textbox id="text1" runat="server" text=""> </asp:Textbox> <asp:CustomValidator id="CustomValidator1" runat=server ControlToValidate = "text1" ErrorMessage = "You must enter at least 8 characters!" ClientValidationFunction="validatefunction" > </asp:CustomValidator>