Design, develop and maintain accessible documents for a semantic web

Document validation and analysis Extension for Firefox, Mozilla and Netscape

Easy to use interface to many free and commercial online validation and analysis services. Validate, analyze, view and inspect documents containing HTML, XHTML, CSS, RDF, RSS, XML, P3P, hyperlinks, metadata and many more. Check Section 508 and WAI compliance of your documents with many helpful services.

New in Checky 2.5



You need a running Firefox, Mozilla or Netscape Browser to install Checky. Read known issue about Checky and Web Developer in Firefox, Mozilla and Netscape!

Restart your Browser! A nice installation tutorial for Firefox extensions is available at Tutorial Center.



You must uninstall/remove all versions of Checky before release 2.2. You can do this in Firefox with the Extension Manager, or in Mozilla and Netscape with the Extension Uninstaller mentioned in more useful extensions.


Please update Checky in Firefox from version 2.2/2.3/2.4 to 2.5 with the Firefox > Extension Manager and mozilla update. Do a normal Install if mozilla update is not working, or needs some more time for mirroring.

Mozilla / Netscape

Just Install Checky 2.5 if you have Checky 2.2/2.3/2.4 previously installed.


Checky - Agent

Combine more than one service with "Checky - Global Preferences -> Checky Agent" (Checky Agent preferences screenshot) and start all with Ctrl+Shift+A on Microsoft® Windows and Cmd+Shift+A on Mac OS X systems. Throughout this page, Ctrl/Cmd will be used.

For example, browse to and press Ctrl/Cmd+Shift+A. Checky - Agent starts and a new Tab (default setting) with W3C® Markup Validation Service opens. Checky prepares and submits the online form. The result is displayed in the same Tab or Window.

Attention with slow internet connections! Maybe loading a service page takes more than 4 seconds (default setting) and Checky tries to prepare the form before displayed. In this case, please go back to the Tab or Window with the original page and try again. After your Browser has cached the page on your local hard drive, 4 seconds should be enough to display it in time. Change "Checky - Global Preferences -> Set preferences after (in seconds)" from 1 to 10 seconds if you need different settings.

Checky - Context menu

Start Checky - Agent and separate services with the Checky Context menu (Checky - Context menu screenshot). Please click right with your mouse button in a Tab or Window with a page or document to access this menu.

Checky - Tools menu

Select " Tools -> Checky" in your favorite Browser menu to access Checky - Global Preferences, start Checky - Agent and individual services, and read more about Checky on the web.

Checky - Global Preferences

Use "Checky - Tools menu - > Preferences" in all Browsers. In Firefox an Extension Manager gives access to Checky - Global Preferences (Checky - Global Preferences screenshot). In Mozilla and Netscape Checky extends the standard preferences dialog. Please notice "Preferences dialog in Firefox hides Checky options".

Service - Preferences

Change execution options for each service in Checky - Global Preferences (e.g. W3C® Markup Validation Service Screenshot), so you don't have to loose your personal settings all the time.

Internal documents and locations

Checky saves resources from internal locations automatically in a temporary directory. You can change the default directory in "Checky - Global Preferences -> Save intranet documents before uploading in" to a more useful location. You must define all internal location URL's in "Checky - Global Preferences -> Intranet URL's" in a comma separated list. Example:,localhost,http://intranet

Known issues

Checky and Web Developer in Firefox, Mozilla and Netscape

Web Developer uses Ctrl/Cmd+Shift+A as default shortcut for local HTML document validation. If you install Web Developer after Checky, local HTML document validation from Web Developer fires and not Checky - Agent. In this case please open "Web Developer Options -> Keys" (Web Developer Options screenshot) and change shortcut for "Validate local HTML" from "Ctrl+Shift+A" to another key. . Installations of Checky after Web Developer are not affected.

Preferences dialog in Firefox hides Checky options

The Checky preferences dialog in Firefox Extension Manager is not resizing and some options aren't visible. We don't want to touch this Firefox behavior! Please use the "Checky - Tools menu" to access Checky preferences in Firefox. After resizing here, the preferences dialog in Firefox Extension Manager shows all available options.

Browser compatibility

Sorry but we don't have much time, testing Checky on many different environments. Please help and submit a compatibility report to checky-development Mailing List. Adobe® Acrobat Reader® 7.0 user can submit a compatibility report with our experimental PDF form.

Table 1 - Checky Browser compatibility matrix (*not yet tested)
Operating System Firefox 1.0 Mozilla 1.7.x Netscape 7.2 Mozilla 1.8a6
Windows XP SP1/SP2 supported supported supported supported
Debian Linux supported supported * *
Mac OS X 10.3.7 supported * * *


Please note before using Checky! Visit all service web sites for more information about terms of usage.


List of services in alphabetical order:

Planned in next release of Checky:

Debian package

Debian Linux users can download Checky as Debian package.

More useful Extensions

Please check mozilla update and for more Extensions and new releases.


Please report Bugs, browse old Bugs, participate in forums, sent comments or jump into code.


Thank you, to all submitting bugs and contributing. Thanks to Jim Massey ( and Chris Neale ( Special thanks to Mike Hommey for Debian packages.

Previous releases

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