Re: CAPTION element for OBJECT?

E. Stephen Mack (estephen@emf.net)
Thu, 10 Jul 1997 12:46:16 -0700


Message-Id: <3.0.3.32.19970710124616.00765d78@emf.net>
Date: Thu, 10 Jul 1997 12:46:16 -0700
To: www-html@w3.org
From: "E. Stephen Mack" <estephen@emf.net>
Subject: Re: CAPTION element for OBJECT?
In-Reply-To: <3.0.2.32.19970710085015.008825c0@undergrad.math.uwaterloo.

I wrote:
>> However, including CAPTION as a valid content element for OBJECT
>> is somewhat problematic.  HTML 4.0's OBJECT definition requires
>> OBJECT-aware browsers to not display any of the contents of the
>> OBJECT element (to allow alternate renderings for non-OBJECT-
>> compliant browsers).

Liam Quinn <liam@htmlhelp.com> replied:
> I know, which is why I think we should do this now before too
> many browsers start implementing OBJECT.  (From what I
> understand, the Big Two's current OBJECT implementations are
> badly butchered already.)

Speaking for Windows 95 implementations: Navigator 3.01 and 4.01 do
not understand OBJECT, but correctly display the OBJECT's contents
as an alternate.

MSIE 3.02 and 4.0 (platform preview 1) do not understand an OBJECT
without a TYPE attribute; the requested height and width are
allocated but nothing is displayed (except a missing icon in
4.0).

If you do specify a MIME type, then you'll get a warning when you
view the page.  The type of warning you get depends on what
"security mode safety level" you're in.  MSIE defaults to "High"
safety level.  This level gives you a warning that the "ActiveX
control" is not known to be safe and so was disabled.  The page is
rendered minus the OBJECT (which is given a missing icon in
4.0).

At "Medium" safety level, you get the choice for each OBJECT
of whether or not it is "safe to execute this command."  Choosing yes
correctly renders the OBJECT in 4.0.  3.02 does not display the OBJECT
and doesn't ask about further OBJECTs.

At "None" safety level, there is no prompt and the objects are rendered
correctly by 4.0 and not displayed by 3.02.  (To change safety
level, View | Options | Security, choose the Safety Level button, and
select one of the three levels.)

At no point did 3.02 or 4.0 display the OBJECT's contents, even when
it was not able to display the OBJECT.

I used this quick test code:

<OBJECT data="earth.gif" type="image/gif" height=200 width=100>
  The <STRONG>Earth</STRONG> as seen from space.
</OBJECT>

<OBJECT data="chimes.wav" type="audio/wav" height=50 width=50>
  A song
</OBJECT>

The image appears in a framed region with scroll bars.  The
presence of the scroll bars and some default margin space are
not as expected, and cause the image to be obscured.

The WAV file is automatically executed using a separate
Active Movie window.  The space allocated on-screen for the
WAV is filled with a blank gray square; right-clicking in this square
allows you to "RUN" the sound again.  Sometimes I saw a black square
filled with 00:00.  Sometimes the Active Movie window had display
anomalies.  After displaying OBJECTs, IE tended to crash immediately
afterwards.  I did test embedding an HTML OBJECT, and it was displayed
briefly before IE crashed.

By the way, IE must be your default browser for OBJECTs or
attached style sheets to work at all.

Since 4.0 is an early release, it is not intended to be fully functional.
At least core support is there.  We'll have to see how this behaviour of IE
changes in future releases of 4.0, and how Navigator begins to add support
for OBJECT.
-- 
E. Stephen Mack <estephen@emf.net>          http://www.emf.net/~estephen/