The LibreJS project is seeking more JavaScript programmers to help maintain this browser extension. If you want to help, send an email to <>.


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GNU LibreJS aims to address the JavaScript problem described in Richard Stallman's article The JavaScript Trap. LibreJS is a free add-on for GNU IceCat and other Mozilla-based browsers. It blocks nonfree nontrivial JavaScript while allowing JavaScript that is free and/or trivial.

Downloading LibreJS

In GNU IceCat or any Mozilla browser, you can install LibreJS by clicking on this link and following the subsequent instructions: librejs-6.0.9.xpi (430k).

The LibreJS source files can be found via HTTPS: librejs-6.0.9.tar.gz (912k). Or FTP: It can also be found on the GNU mirrors. This link will automatically select a mirror for you. LibreJS is also available at the Mozilla Add-ons site. Due to Mozilla's review process, the version of LibreJS available at the Add-ons site is often outdated. This isn't in our control.

Releasing Your JavaScript as Free Software

If you administer a website, please read instructions on how to set your JavaScript free so that it respects your users' freedom. This is also documented in this section of the LibreJS manual.


Documentation for LibreJS is available online, as is documentation for most GNU software.

Mailing lists

LibreJS has the following mailing lists:

Announcements about LibreJS and most other GNU software are made on info-gnu (archive).

Security reports that should not be made immediately public can be sent directly to the maintainer. If there is no response to an urgent issue, you can escalate to the general security mailing list for advice.

Getting involved

Development of LibreJS, and GNU in general, is a volunteer effort, and you can contribute. For information, please read How to help GNU. If you'd like to get involved, it's a good idea to join the discussion mailing list (see above).

Test releases
Trying the latest test release (when available) is always appreciated. Test releases of LibreJS can be found at (via HTTP) and (via FTP).
For development sources, issue trackers, and other information, please see the LibreJS project page at
Git Repository

LibreJS development happens in this git repository: You can clone that repo with the command: git clone git://

LibreJS is currently being maintained by Nik Nyby and Ruben Rodriguez. Please use the mailing lists for contact.


LibreJS is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version.


Special thanks go to GNU Chief Webmaster Jason Self for his feedback, testing, and support.

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