This is restartless add-on.
File -> Open -> All Files -> nosleep@om.xpi
You can manage it in about:addons page.

This add-on creates the button on the toolbar
Default toolbar: "Browser Con&figuration"
Create "extensions.nosleep@om.toolbar" string preference (in about:config page)
to override default.

Modes:
gray icon - turn off functionality

blue icon - prevent screensaver when fullscreen

green icon - prevent screensaver when html5 video played (the icon turns red)
This add-on does not check iframes for video.
It works for youtube.

pink icon - unconditionally prevent screensaver



Edited 3 time(s). Last edit at 12/26/2020 07:28AM by Kris_88.