INSTALLATION (Firefox Version >=57 or Chrome)

Production version:

The webextension is available for Firefox (Version>=57) and Chrome:

Firefox
Download: Firefox: Addons
Chrome
Download: Chrome: extensions

Development version: 

You have to download and install the latest version of the extension that is available in GitHub (https://github.com/mgueury/html_validator/).
See instruction here

PREVIOUS VERSION (Firefox Version <=56)

DOWNLOAD BETA VERSION  

FIREFOX 44.0x or later Choose your platform :

  Version
4.0
...
48.0 and later
Windows 32
Windows 64
Linux 32
Linux 64
Mac OSX (Universal)
0.975 beta Download HTML Validator (beta channel) X X X
Other platforms

Please check the forums



Source code
Github Html Validator



FIREFOX 10.0x or later Choose your platform :

  Version
4.0
...
10.0 and later
Windows 0.952 Download HTML Validator for Windows 32 bits X X X
Linux 32 bits 0.952 Download HTML Validator for Linux 32 bits X X X
Linux 64 bits
0.952
Download HTML Validator for Linux 64 bits X
X
X
Mac Os X (universal build)
0.952B
Download HTML Validator for Mac OS X X
X
X
Other platforms

Please check the forums



Source code (2012-01-24)
0.952 Download the source code



Thanks to EclipseChasers2 and Tom for the compilation of the Linux64 and MacOsX versions (see Forums)

FIREFOX 9.0x Choose your platform :

  Version
4.0
...
10.0
Windows 0.951 Download HTML Validator for Windows 32 bits X X X
Linux 32 bits 0.951 Download HTML Validator for Linux 32 bits X X X
Linux 64 bits
0.951
Download HTML Validator for Linux 64 bits X
X
X
Mac Os X (universal build)
0.951 Download HTML Validator for Mac OS X X
X
X
Other platforms

Please check the forums



Source code (2011-12-1)
0.951 Download the source code


FIREFOX 8.0x Choose your platform :

  Version
8.0
Windows
0.912 Download HTML Validator for Windows X
Other platforms

Please check the forums

Source code (2011-09-19)
0.912 Download the source code

FIREFOX 7.0x Choose your platform :

  Version
7.0
Windows
0.911 Download HTML Validator for Windows X


FIREFOX 6.0x Choose your platform :

  Version
6.0
Windows
0.910 Download HTML Validator for Windows X

FIREFOX 4.0x or 5.0.x Choose your platform :

  Version
4.0
5.0
Windows
0.906 Download HTML Validator for Windows X
X

FIREFOX 4.0.x ONLY Choose your platform :

  Version
3.6
4.0
Windows
0.904 Download HTML Validator for Windows
X
Linux 32 bits
0.904 Download HTML Validator for Linux 
X
Linux 64 bits 0.904 Download HTML Validator for Linux 64bits 
X
Mac OsX Intel 32 0.904 Download HTML Validator for MacOS 32bits
X
Mac OSX Intel 64 bits 0.904 Download HTML Validator for MacOS 64bits
X
Mac OSX Intel 32/64 bits (universal build) 0.904 Download HTML Validator for MacOS 32/64bits universal build
X
FreeBSD 7
TODO

OpenBSD 64 bits
TODO

Other platforms
See here

Source code (2010-12-12)
0.904 Download the source code


The extension XPI is now 2.0 Mb big ... The SGML parser is quite complex :-) But seems to work really well. The validation for the biggest pages I saw are below the 1/100 sec for both algorithms.