Michael Langley

http://www.nu22.com/firefox/optionsb/

Page validator

Updated at By Michael Langley
The Page Validator is a Firefox add-on that checks for webpage validity using W3C website validation service, highlighting any errors or warnings for users to address.

CSS validator

Updated at By Michael Langley
The CSS Validator is a Firefox add-on that audits webpages for CSS compliance using the W3C CSS Validator, ensuring accurate and reliable code every time.

RSS validator

Updated at By Michael Langley
Firefox add-on, RSS validator, enables webpage validation through W3C RSS Validator in one step.