Validating User Input in ASP.net

* All validation controls are derived from the BaseValidator class
* Validation controls always perform validation checking on the server
* Validation controls also have complete client side implementation that allows browsers that support DHTML to perform validation on the client

Validation controls are:-
RequiredFieldValidator Control
CompareValidator Control
RangeValidator Control
RegularExpressionValidator Control
CustomValidator Control
ValidationSummary Control