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GNU LibreJS, or simply LibreJS, is a free software web browser extension for Mozilla Firefox-based browsers, created by the GNU Project. 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" described by Richard Stallman,[2] a situation in which many users unknowingly run proprietary software in their web browsers.[3]

LibreJS icon.png
LibreJS on Wikipedia.png
GNU LibreJS 6.0.9 showing the blocked elements on the English Wikipedia main page.
Developer(s) Ruben Rodriguez, Nik Nyby
Stable release
6.0.13 / 4 May 2016; 12 months ago (2016-05-04)[1]
Development status Active
Type Browser extension
License GNU GPL v3[2]



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.[4] It can also work with Tor.[5]

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 break while using the add-on, due to the pervasiveness of proprietary JavaScript code on the web.[6] Nevertheless, programmer and activist Richard Stallman supports the usage of GNU LibreJS.[3]

See alsoEdit


  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. ^ "GNUzilla and IceCat". Free Software Foundation. 
  5. ^ n8willis (2014-12-03). "GNU LibreJS 6.0.6 released". 
  6. ^ wtheaker (2013-10-23). "LibreJS reaches version 5.4". Free Software Foundation. 

External linksEdit