Wonderful!

This is the only fullscreen addon I've found that at least partially works. It will open your tab in fullscreen, but you have to press control-shift-f every single time, and once you are in fullscreen, you can't just logically mouse up to the top to show the bookmarks and tabs you've hidden, just nothing appears.

Awesome! Thought it didn't work at first because it doesn't work on mozzilla firefox pages and you might have to restart firefox. Thanks a lot

The add-on does what is says, but is kinda pointless as Firefox already goes complete fullscreen with F11. However only if browser.fullscreen.autohide (about:config) is set to true, which is the default setting anyways.

Does what it's supposed to, using the full screen Web API to also remove the title URL bar. Thanks.

1 thing: you might want to add the add-on icon to be a toggle for fullscreen?

Works flawlessly for me! (as of Feb 2019, FF 65.0)

I don't get what some of the other reviews are complaining about, because I'm really glad to finally have true fullscreen again in Firefox.

One limitation is indeed that you can't change the keyboard shortcut in the addon settings, but I solved it by using an external tool (Karabiner), mapped the standard cmd-shift-f to the addon's ctrl-shift-f shortcut.

Summary: Get this addon if you want real fullscreen back! And, thanks a lot Trishul for this addon.

Google Docs is using the same shortcut. Could you consider adding an option to change the shortcut? Thanks!

For some reason it didn't work until I restarted Firefox, but now it works flawlessly. I use this add-on to remove distractions so I can concentrate on my work. Thank you whoever built this!

Doesn't work on Flash game sites that have input bar focused —so it's useless like the userChrome.css trick. Make the full screen trigger without window focus. Nevermind, it's a glitch in Habbo site, I'am back to using this userChrome script: https://www.userchrome.org/what-is-userchrome-css.html

Superb. Works a treat and it does it quickly and looks absolutely perfect. Pressing ESC gets me back to the normal browser view, which is intuitive. There are many times, particularly, when I am writing or designing, that I like to go into total full screen mode (i.e. without the tabs and all the other clutter) and this does exactly that and does it more elegantly than anything else I have come across. Thank you for clearing up my screen so well :-)

UPDATE 2021-08-22:
Les Merlotta's trick for Mac from 2020-10 is still working on Firefox 91.0.1 Mac:
"Type "about:config" in your Firefox address bar (like going to a website), click "Accept the risk and continue". Then copy/ paste "full-screen-api.allow-trusted-requests-only" and change it to false."

OLDER COMMENT:
Thank you Trishul, good job. Running fine in macOS 10.10.13 High Sierra with Ctrl+Shift+F. I like that Cmd+Shift+F remains for the default full-screen behavior.

Just one request: please add an option page where to toggle if FS mode shall be left or kept when clicking onto a link (and maybe another option when leaving a domain).

It didn't work at first. But it works fine after running the Java script. Thanks for a very useful add-on.

As of 15 January 2018, this is the only add-on that will allow fullscreen functionality with no menu/nav bars on OSX 10.12.6 (FF 57.0.4). The browser.fullscreen.autohide function is broken for this machine configuration.

Feature request for this add-on: please add an icon that can be added to the menu bar that does the CTRL+SHIFT+F shortcut with one click.

It works (mostly) as intended. Four things to note:
1. control+shift+F is the keyboard shortcut, even on a Mac. This is actually very helpful. Since it does not override the default fullscreen behavior, both fullscreen modes are within reach (command+shift+F calls for the default fullscreen behavior).
2. Due to some restrictions it does not work on addons.mozilla.org. This might lead to some false reports saying it does not work.
3. As soon as you do anything in a webpage (click a link, search with Google, etc.), it will revert back to the default fullscreen behavior.
4. It requires access to "all data in all websites", so regular code audits might be needed to ensure that it does not do anything malicious.