HTML VALIDATOR (based on Tidy and OpenSP)
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
in the status bar
when browsing. The details of the errors are seen when looking the HTML
source of the
The extension is based on Tidy and OpenSP.
originally developed by the Web Consortium W3C.
extended and improved by a lot of persons. Both algorithms are embedded
Mozilla/Firefox and makes the validation locally on your machine,
without sending HTML to a third party server.
There is also an automatic "Clean up" button that will
do his best to propose you a cleaned version of your page, without
- HTML Tidy is a helpful program that tries to help
people to correct their
HTML errors. It finds HTML errors and classifies them in 3 categories:
- errors: HTML
cannot fix or understand.
- warnings: HTML
that Tidy can
- (optional) accessibility
warnings: HTML warnings
for the 3 priority levels defined in W3c
- OpenSP, is SGML parser, is a
algorithm. It is the same
program running inside http://validator.w3.org/.
now, you can embed it in Firefox !
FIREFOX 57 + CHROME
Firefox old XUL extension do not work anymore with Firefox 57.
HTML Validator 0.98 is the first Web Extension version. It is a
complete rewrite of the code.
The extension works now differently:
Some features from the 0.97 are still missing. See here for more details.
- There is a new tab in Developer tools: Html Validator.
- The validation happens only when the "Developer
Tools" is open.
- The extension uses a new version of Tidy 5 compiled
from C to
- It works in Chrome
0.975 beta channel - FOR FIREFOX 40 and later - Windows
32bits, 64 bits, Linux 32 bits, 64
bits and Mac OS X
New in Version 0.975 beta, Lot of fixes to get compatible with Firefox
48 and Electrolysis. See
New Beta Channel: it
is easy to install the beta version !
New in Version 0.965, Several fixes for compatibility with Firefox 44
New in Version 0.964, One single file for all platform, added Windows
64 bits support See
0.9.1.2 - FOR FIREFOX 8.0 ONLY - Windows only (for now)
Since Firefox 4+ and rapid releases, XPCOM has been unfrozen. (see here)
This means practically that every extension by binary, like this one,
needs to be recompiled for each Firefox version.
Due that Firefox version will follow one after the other, the current
model of the extension is not viable anymore at long term.
I will need to change the structure deeply in a next version. Help is
0.9.1.1 - FOR FIREFOX 7.0 ONLY - Windows only (for now)
0.9.1.0 - FOR FIREFOX 6.0 ONLY - Windows only (for now)
0.9.0.6 - FOR FIREFOX 5.0 ONLY - Windows only (for now)
0.9.0.4 - Most platforms available
- Due to Numerous changes due to Firefox 4.0, the extension 0.9 is
compatible only with Firefox 4.0
- The browser icon is in the add-on bar. The status bar does not exist
in FF 4.0 anymore.
This means too that all platforms binaries will need to be recompiled.
Look the source and the forum if you want to help on the
- To enable HTML 5 validation, it is possible to validate page with W3c
FIREFOX 3.6 and below
Download : version
0.8.6.1 - Release notes.
guide, translation, forums)
- Translations: DA KO LT SK SL
- Works with Firefox 3.6
- Works with Seamonkey 2.0
- Fix of warning in sp_start.html for some translations
If you want to see some images, click on one of the
The extension has 3 main features:
- The HTML validation is done when browsing. The
result is shown on the form of an icon
in the status bar.
- If the page contains HTML frames or iframes, you can
the validation result of the main page and the frames.
- The detail of the validation can be seen when looking
source of the page.
- Tidy validates the HTML code and displays the result
a compiler for a programming language.
- The validation is done based on the source and not by
making a second request to the Web Server.
- The screen is splitted in 3 parts. Above the source
HTML, and below, the list of the errors and the explanation of the
- The explanation of the errors are a personal effort
HTML specification understandable. Because I must admit, that not all
HTML errors are easy to understand. For example,
generates an error
</p>. And without an explanation about inline and block
HTML, from far point of view, this looks like correct HTML.
- It is also possible to ask HTML Validator to propose
version of the page in HTML or convert it to XHTML.
- You can compare the cleanup version and the original
version in 2 tabs. (source and preview)
In comparison with web HTML validators like http://validator.w3.org,
- the data is not
sent to a 3rd
- So, there is no problem with firewall to validate
generated HTML that are in intranets. What you can not do with web
validators, except by saving the file and upload it.
- You have also not the problem of people not daring to
validate their pages by using other people machines.
- the validation is done automatically and just by looking
- it is easy to validate dynamic page. Dynamic pages
available in the browser and you validate when you see them.
- it is a gui. So, the validation is faster and the
has more possibilities.
- Just press CTRL+U (page view) and all yours errors
there.It is done based on the page source and without accessing a
second time the web server to get the HTML source.
- If it is your website you try to correct, just press
in the view source to revalidate the result after correcting the errors.
HOW DOES IT WORK
The extension includes:
presentation of the results.
- Some HTML pages for the help on the HTML errors and
- A dynamic C library, .DLL or .SO, that contains:
- The original Tidy source code
- The original OpenSP source code
- Some C code to glue make tidy XPCOM compliant and give the ability to
I NEED HELP
If you are interested in helping or have ideas to improve the
extension, do not hesitate.
See the roadmap.
Forum : http://www.htmlpedia.org/phpBB/
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For any issue, please contact me <Marc