Try headless mode: https://developer.mozilla.org/en-US/Firefox/Headless_mode

Thank you for your help. This is not what I need because the webpage is not visible. I need a way to start Firefox in fullscreen mode (kiosk mode), like if you press the F11 key (no pulldown menus, no title bar, ...).

I don't think this is possible.

Hallo it is posible. Linux: https://forum.ubuntuusers.de/topic/kiok-modus-firefox-quantum/

You make in ~/.mozilla/firefox/PROFIL.default/chrome/userChrome.css with content:

@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"); /* set default namespace to XUL */ ,#fullscr-toggler { display:none!important; }

or in Windows in C:\Users\user\AppData\Roaming\Mozilla\Firefox\Profiles\yourProfile.default\chrome\userChrome.css

The new directory chrome must manuell created. By your self. The , bevor fullscr-toogler must removed and left side.

^: That is something different and is about to prevent showing the toolbars if you hover the mouse to the top of the page in Full Screen mode (F11).

The OP wants to start Firefox in Full Screen mode.

The kiosk extensions aren't compatible with Firefox 58+ (WebExtension).

• https://addons.mozilla.org/en-US/firefox/search/?q=kiosk

Knarf68 said

Hallo it is posible. Linux: https://forum.ubuntuusers.de/topic/kiok-modus-firefox-quantum/ You make in ~/.mozilla/firefox/PROFIL.default/chrome/userChrome.css with content: @namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"); /* set default namespace to XUL */ ,#fullscr-toggler { display:none!important; } or in Windows in C:\Users\user\AppData\Roaming\Mozilla\Firefox\Profiles\yourProfile.default\chrome\userChrome.css The new directory chrome must manuell created. By your self. The , bevor fullscr-toogler must removed and left side.

Thanks!

Thank you for your answer.

As user "cor-el" wrote, this only prevents that (in full screen mode by pressing the F11 key) the FireFox menu appears if you move the mouse to the top of the page.

FireFox however starts in normal mode and not in full screen (kiosk) mode, you still have to press the F11 key.