Disable firefox fullscreen warning with html5 stuff?

Whenever I go fullscreen in html5 things it puts a message at the top saying you're now in fullscreen, the problem is that this message totally stops you being able to do anything else until it disapears. So if I open a youtube video in fullscreen I can't pause it or do anything until I wait for the message to disapear. How can I disable the message totally?

Solution 1:

This is the security feature, but yes it's annoying if you're on trusted site and the message popups every time you enter full screen.

Solution: enter about:config in address-bar, and search for full-screen-api.approval-required and set it to false

You're done!

Solution 2:

UPDATE: OCT-2019 to cover Firefox Quantum:

Enter about:config in Firefox address-bar and search for the keyword "full-screen". Identify following listing and change their respective values as mentioned against them below:

full-screen-api.transition-duration.enter - 0 0
full-screen-api.transition-duration.leave - 0 0
full-screen-api.transition.timeout - 0
full-screen-api.warning.delay - 0
full-screen-api.warning.timeout - 0

(Archival Notes) FireFox 42

Option "full-screen-api.approval-required", no longer hides the Website is Now Full Screen warning. In previous versions setting it to "false" could resolve the problem. They are putting a new option in i.e. (full-screen-api.warning.timeout "0") that will do the same thing, but it will be rolled out in FireFox 43.

You can change the fade in/out animation when going full-screen by setting:

full-screen-api.transition-duration.enter 0 0

full-screen-api.transition-duration.leave 0 0

Note/Warning - Defaults are 200 200 and 0 0 will remove them completely.

Keep in mind these are put in because they are a security features to help stop Phishing Attacks. So either wait till Firefox should enable "full-screen-api.warning.timeout" option in next few releases OR use above at your own risk...

Solution 3:

Since Firefox 43 (still working in 59)

1) enter about:config in address-bar
2) set full-screen-api.warning.timeout to 0