[whatwg] api for fullscreen()

Smylers Smylers at stripey.com
Wed Feb 3 16:19:53 PST 2010

Brian Campbell writes:

> > As I understand it, the risk with full-screen view is that a
> > malicous site may spoof browser chrome, such as the URL bar, thereby
> > tricking a user who isn't aware the site is full-screen.
> This is addressing a different scenario; not malicious sites per-se,
> but sites that insist on being displayed full screen.

OK.  That's 'merely' an annoyance, not a security threat.  There are
lots of ways authors can be obnoxious if they choose; I'm not sure it's
desirable, or even possible, to outlaw them.

> My boss was very insistent about content being displayed full screen,
> to make the experience more immersive and reduce distractions ...
> "Please press the button to enter full-screen mode and start the
> program", and the program would not start until full-screen mode was
> entered. I could imagine games, and other content doing the same as
> well.
> I think that this behavior is fairly user hostile, however.

In general user-agents are allowed to display content in anyway that a
user has configured them to do, regardless of what the spec gives as the
normal behaviour.

> If a user wishes to view content scaled up to fill the window, without
> the distractions of navigational links, comments, descriptions, and so
> on, they don't usually have a way to do this. If it were possible to
> use the full-screen button, but deny permission to actually go full
> screen, and have that simply display the content in the full window
> exactly as if it were full screen, it would give the users more
> control over how they view the content.

I've seen Firefox options (possibly in an extension) which allow users
to tweak which toolbars and the like are still displayed when in
full-screen view.

If a browser (or an extension) wished to implement full-screen view as
still having borders, the title bar, status bar, and so on then it
could.  And there's nothing an author could do about it.

> Content authors should not be able to force fullscreen mode on users,
> however, so I think it would be best if the spec allows UAs to send
> the fullscreen event and set the fullscreen pseudoclass even if the
> content is not actually filling the entire screen.

To say that slightly differently: authors can dictate that certain
output is only displayed when in full-screen view; but they have no
control how full-screen view looks for a particular user and user-agent.

> All the spec would have to say to cover all of the possible
> implementations is that the fullscreen events may be sent even if the
> content isn't actually filling an entire screen,

Allowing that behaviour is entirely reasonable.  Though I think it
should be covered by a more general statement that user-agents may
display things however they want if so-configured, rather than just
stating it for this particular narrow case.

Watch fiendish TV quiz 'Only Connect' (some questions by me) Mondays at
20:30 on BBC4, or iPlayer: http://www.bbc.co.uk/programmes/b00lskhg

More information about the whatwg mailing list