Many site issues can be caused by corrupt cookies or cache. In order to try to fix these problems, the first step is to clear both cookies and the cache. The Firefox cache temporarily stores images, scripts, and other parts of websites while you are browsing.
Note: This will temporarily log you out of all sites you're logged in to. To clear cache and cookies, do the following:

1. Tap the menu icon located at the top right corner. This is the icon with 3 bars. On older Android devices you'll have to press the hardware menu key and then tap More.
2. Tap Settings.
3. After that, you will be taken to the settings screen. In the settings screen, look under the section Privacy & Security and select Clear private data.
4. You will then be taken to a list of what can be cleared. Select the following 2 for deletion:
   • Cookies & active logins
   • Cache
5. After those have been selected, tap the Clear data button to actually clear the cache and cookies.

Did this help you with your problems? Please let us know!

no help at all

Are you using the flash plugin, did you install it?

SEE: How do I watch Flash videos with Firefox for Android?

flash has nothing to do look at this http://www.youtube.com/html5 HTML5 is a new browser technology that allows us to show videos without the Flash plug-in. Notes

   Fullscreen support is partially implemented. Pressing the fullscreen button will expand the player to fill your browser. If your browser supports a fullscreen option, you can then use that to truly fill the screen.

so firefox does not have the full screen icon

dolphin and boat browsers have

Being from youtube with entre play then margin Right side inside margin middle entre to me can do in fullscreen.

Assuming YouTube has not overridden Firefox's default. Long pressing on the video will bring up a menu with several options including Fullscreen.

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