Firefox blocking Facebook Js

A simple google search leads to this page: https://developer.mozilla.org/en-US/Firefox/Privacy/Tracking_Protection

You should be able to deactivate that feature right where the message appears, or via about:config. It should actually be deactivated by default afaik.

From the client side, you can't. This is security policy Firefox. You can read about this issue in thread: https://bugzilla.mozilla.org/show_bug.cgi?id=1226498