If one of your validations is complicated and does not fit in any validators, what you do?
The best way is to go for CustomValidators. The sample code for a custom validator is shown below which checks that the textbox should not have zero value.
Validator id="CustomValidator1" runat="server" ErrorMessage="Number not divisible by Zero" ControlToValidate="txtNumber" OnServerValidate="ServerValidate" ClientValidationFunction="CheckZero" />
Input:
TextBox id="txtNumber" runat="server" />
t language="javascript">