esto es lo que dice MDC acerca del fullscreen,
Cita:
Iniciado por https://developer.mozilla.org/en/DOM/window.open fullscreen
Do not use. Not implemented in Mozilla. There are no plans to implement this feature in Mozilla.
This feature no longer works in MSIE 6 SP2 the way it worked in MSIE 5.x. The Windows taskbar, as well as the titlebar and the status bar of the window are not visible, nor accessible when fullscreen is enabled in MSIE 5.x.
fullscreen always upsets users with large monitor screen or with dual monitor screen. Forcing fullscreen onto other users is also extremely unpopular and is considered an outright rude attempt to impose web author's viewing preferences onto users.
Note on fullscreen
Supported in:
fullscreen does not really work in MSIE 6 SP2.