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How do I manage Firefox fullscreen permissions on HTML5 videos?

  • 3 replies
  • 3 have this problem
  • 34 views
  • Last reply by cor-el

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I accidentally set youtube's HTML5 player to disable full screen - how do I re-enable it or manage my permissions for HTML 5 full screen video?

I accidentally set youtube's HTML5 player to disable full screen - how do I re-enable it or manage my permissions for HTML 5 full screen video?

Chosen solution

That appears to be stored as a permission.

You can open the about:permissions page via the location bar and select www.youtube.com in the left pane.
You will notice a full screen select with three choices and with Block currently selected.
You can set it to Allow or to Always Ask as you like.

Also accessible via Tools > Page Info > Permissions


Read this answer in context 👍 3

All Replies (3)

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Try to clear the YouTube cookies

  • Tools > Options > Privacy > Cookies: "Show Cookies"

YouTube may also be using local storage to store data.

I have this 'cookie' in local storage to set the volume level:

yt-player-volume: {"volume":100,"nonNormalized":null,"muted":false}

You can delete the webappsstore.sqlite file in the Firefox Profile Folder to clear all data in local (DOM) storage.

See also "Storage location and clearing the data":

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Neither option works, unfortunately. Have already tried clearing cookies before resorting to the forum.

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Chosen Solution

That appears to be stored as a permission.

You can open the about:permissions page via the location bar and select www.youtube.com in the left pane.
You will notice a full screen select with three choices and with Block currently selected.
You can set it to Allow or to Always Ask as you like.

Also accessible via Tools > Page Info > Permissions


Modified by cor-el