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GNU LibreJS 6.0.9 showing the blocked elements on the English Wikipedia main page.
GNU LibreJS 6.0.9 showing the blocked elements on the English Wikipedia main page.
Developer(s)Ruben Rodriguez, Nik Nyby
Stable release
7.18.1 / 7 November 2018; 4 months ago (2018-11-07)[1]
Repository Edit this at Wikidata
TypeBrowser extension
LicenseGNU GPL v3[2]

GNU LibreJS, or simply LibreJS, is a free software web browser extension for Mozilla Firefox-based browsers, created by the GNU Project.[2] Its purpose is to block nonfree nontrivial JavaScript programs and allow free or trivial JS in a user's web browser. The add-on was created to address the so-called "JavaScript Trap"[3] first described by Richard Stallman in 2009,[4] a situation in which many users unknowingly run proprietary software in their web browsers.


GNU LibreJS aims to block nonfree JavaScript programs that are present in many websites. It is developed as part of the GNU Project by Ruben Rodriguez and Nik Nyby[2] and is included by default in the GNU IceCat browser.[5] It can also work with Tor.[6]

The add-on allows site whitelisting and has an e-mail detection system for users to contact page webmasters in order to persuade them into making their JavaScript code compliant with LibreJS.[1] According to the Free Software Foundation, many websites (if not whitelisted) break while using the add-on, due to the pervasiveness of proprietary JavaScript code on the web.[7] Nevertheless, programmer and activist Richard Stallman supports the usage of GNU LibreJS.[3]

See also[edit]


  1. ^ a b "LibreJS - News". Savannah.
  2. ^ a b c "GNU LibreJS". Retrieved 2015-07-23.
  3. ^ a b Richard Stallman. "The JavaScript Trap". Retrieved 2015-07-23.
  4. ^ "The Javascript Trap". 2009-03-24. Retrieved 2018-12-31.
  5. ^ "GNUzilla and IceCat". Free Software Foundation.
  6. ^ n8willis (2014-12-03). "GNU LibreJS 6.0.6 released".
  7. ^ wtheaker (2013-10-23). "LibreJS reaches version 5.4". Free Software Foundation.

External links[edit]