With firefox 54, there seems to be a conflict between synchronous ajax queries performed on window.unload and PrivacyBadger. When the user clicks on a link, the url changes in the URL navigation bar but the page content doesn't update. The user has to reload the page manually.

Although synchronous ajax queries are a very bad idea, and hooking on unload event is probably bad too, it happens to break navigation on some websites (e.g. https://www.logilab.org/).

NOTE: This is specific to firefox

This bug was observed in the following environment:

• PrivacyBadger version: 2016.6.13.1
• Firefox version: 54.0 (64 bits)
• Debian package version: 54.0-1
• Debian Version: Stretch

Steps to reproduce the bug:

 $ git clone https://github.com/adimascio/testff.git
 $ cd testff
 $ npm install
 $ node index.js

Now, open your browser on http://locahost:3000 and try to follow page1 and page2 links.