A bit dissapointed, as the author stated he picked up "Javascript Control by Erwan Ameil" to change it's default behaviour (disabled). But he ended up leaving it disabled by default. So what's the point? I installed this expecting he would keep his word on his comment:
"by meetDeveloper, 6 years ago
I really liked this add-on apart from its default policy, so I forked the Code and edited to change the default policy, and made a new extension https://addons.mozilla.org/en-US/firefox/addon/quick-js-switcher/ , feel free to install that. "