To try the thousands of add-ons available here, download Mozilla Firefox, a fast, free way to surf the Web!Close
Welcome to Firefox Add-ons.
Choose from thousands of extra features and styles to make Firefox your own.Close
Html Validator 0.9.7.4 Requires Restart
by Marc Gueury
HTML Validator is a Mozilla extension that adds HTML validation inside Firefox and Mozilla. The number of errors of a HTML page is seen on the form of an icon
For Online HTML 5 validation, you need 0.962
About this Add-on
The extension can validate the HTML sent by the server or the HTML in the memory (after Ajax execution).
The details of the errors are seen when looking the HTML source of the page.
The extension is based on Tidy and OpenSP (SGML Parser). Both algorithms were originally developed by the Web Consortium W3C. And now extended and improved by a lot of persons. Both algorithms are embedded inside Mozilla/Firefox and makes the validation locally on your machine, without sending HTML to a third party server.
Each algorithm has advantages and inconvenients. The program will give you the choice at startup. But mostly,
- The SGML parser is the same program than the one running behind validator.w3.org.
- Tidy has accessibility check for the 3 levels defined in WAI
- W3 Online validator to validate HTML 5 pages
The extension is translated in 17 languages.
For technical reasons, the extension is available in this site only for:
Other platforms are available here:
The complete list of platforms is
- Linux 32 bits
- MacOs 32 bits
- MacOs 64 bits
- MacOs Universal (32/64 bits)
The old version for Firefox 3 is also available for
- Linux 64 bits
- OpenBSD 32 bits
- OpenBSD 64 bits
- MacOsX PPC
- MacOSX Intel
- Linux PPC
For more information, or other platforms, see: http://users.skynet.be/mgueury/mozilla/
Or the forum:
If you have any problems or questions with the extension please visit the extension home page:
There is a FAQ, download page and translations.
The extension is available on WINDOWS, LINUX, MACOSX. If you have issue installing the extension. Please double-check that you install the one for your OS and your CPU.
This Website shows only the OS version that your browser uses. It contains only a limited number of platforms. (Windows, and Linux 32bits)
You can find the complete list here:
In case of unsolved issues, please e-mail me: email@example.com
The Development Channel lets you test an experimental new version of this add-on before it's released to the general public. Once you install the development version, you will continue to get updates from this channel. To stop receiving development updates, reinstall the default version from the link above.
Caution: Development versions of this add-on have not been reviewed by Mozilla.
- Version 0.9.7.7.beta: