PageKit uses Data::FormValidator to provide easy form validation. Highlights fields in red that user filled incorrectly by using the PKIT_ERRORFONT tag. In addition, error message(s) are displayed using the PKIT_MESSAGES tag. To use, pass an input profile to the pkit_validate_input method.

In addition, you may implement your own custom error handling by using pkit_set_errorfont to set the PKIT_ERRORFONT tags.