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RE: Conditional versus Optional: Preliminary Observations

From: Jon Gunderson <jongund@uiuc.edu>
Date: Fri, 23 Feb 2001 12:38:59 -0600
Message-Id: <4.3.1.2.20010223120022.013b2a70@staff.uiuc.edu>
To: "Hansen, Eric" <ehansen@ets.org>
Cc: "'oedipus@hicom.net'" <oedipus@hicom.net>, w3c-wai-ua@w3.org
It seems it might be better to reference the specification rather than the 
author for what is "conditional" content.  So maybe something like:

<NEW DEFINITION>
Conditional content is content defined through specification.  Some 
conditional content has a direct relationship to accessibility, and other 
conditional content is used for accessibility information and other types 
of information.  The inclusion of conditional content by an author may or 
may not be required by a specification for the content to be considered 
valid.  Even though a specification may not require the author to include 
conditional content, author specified conditional content may be required 
for the resource to be considered accessible.  Specifications typically do 
not require that conditional content be rendered by default, but that it 
must be made available to the user through the user interface under certain 
conditions. Rendering conditions for conditional content include, but are 
not limited to, user agent capabilities, user preferences and bandwith 
available for communication.  For accessibility user preferences is 
typically the condition that is used for conditional content needed for 
accessibility is rendered.  Some mechanisms for providing conditional 
content include the "alt" attribute and the OBJECT element in HTML, and the 
test attributes of SMIL 1.0 and SMIL 2.0.  The rendering semantics (when 
and where) of conditional content may be well-defined in some cases (e.g., 
"alt" and OBJECT in HTML) and less well-defined in others (e.g., "title" in 
HTML).
</NEW DEFINITION>

Something about authors "intent" bugs me, I am not sure what.  If an author 
uses the IMG element of HTML then I guess that signifies that the author 
expects the user to view the image, but I don't know why we need to 
understand the authors intent for this conditional content definition to be 
useful.  I think the definition should emphasize that access to conditional 
content is needed for accessibility and not try to understand the authors 
intent.

Jon

At 12:10 PM 2/23/2001 -0500, Hansen, Eric wrote:
>I think that removing the notion of 'intent' from the definition of
>optional/conditional content is troublesome due to the fact the that
>definition, even without the change, is arguably already too broad. My gut
>feeling is that to remove the constraint of intent would push the definition
>over the edge, making it much too broad.
>
>Consider a possible example of the current broadness of the the definitions.
>Think of a sequence of Web pages, each linked to the next. The first page is
>presented by 'default'; the succeeding pages are only presented under
>certain conditions or circumstances. Does that make the succeeding pages
>'conditional content'?
>
>The current definition does not say much about the grain size of these
>chunks of content (really only through the examples).
>
>By removing the notion of intent, then doesn't one make the scope all the
>broader. Let us consider your suggested definition.
>
>I
> > think we say that it is content the author provides that will
> > be rendered
> > given a certain set of circumstances that include user agent
> > capabilities,
> > user perferences and the bandwidth of the informational exchange.
>
>Especially if we consider that 'user preferences' might include liberal
>access to content through a source view, then under this definition is there
>any information that would _NOT_ be optional/conditional content? Maybe not.
>And if that this the case, then the term 'optional/conditional content' is a
>distinction without a difference and we really should be saying 'all
>content'. But I don't think that we mean 'all content' where we refer to
>'optional/conditional content. So, at this point I would be concerned about
>removing reference to intent.
>
>I think that if intent were removed we would need to look at adding other
>constraints, such as information about grain-size of these chunks of
>content.
>
>
> > -----Original Message-----
> > From: jon gunderson [mailto:jongund@ux1.cso.uiuc.edu]
> > Sent: Thursday, February 22, 2001 11:38 PM
> > To: Hansen, Eric
> > Cc: 'oedipus@hicom.net'; w3c-wai-ua@w3.org
> > Subject: RE: Conditional versus Optional: Preliminary Observations
> >
> >
> > I don't think we need to mention the authors intent in the
> > definition.  I
> > think we say that it is content the author provides that will
> > be rendered
> > given a certain set of circumstances that include user agent
> > capabilities,
> > user perferences and the bandwidth of the informational exchange.
> >
> > Jon
> >
> >
> > On Thu, 22 Feb 2001, Hansen, Eric wrote:
> >
> > > Gregory,
> > >
> > > The suggestion is interesting. If the change were made,
> > would the definition
> > > capture what we mean?
> > >
> > > New, tentative definition of "Conditional content":
> > >
> > > Conditional content is content that the author does not intend the
> > > user agent to render by default, but that the author does intend
> > > to make available to the user through the user interface under
> > > certain conditions. Some mechanisms for providing conditional
> > > content include the "alt" attribute and the OBJECT element in
> > > HTML, and the test attributes of SMIL 1.0 and SMIL 2.0.
> > >
> > > The rendering semantics (when and where) of conditional content may
> > > be well-defined in some cases (e.g., "alt" and OBJECT in HTML)
> > > and less well-defined in others (e.g., "title" in HTML).
> > >
> > > Note: The Web Content Accessibility Guidelines 1.0 requires that
> > > authors provide text equivalents for non-text content. This is
> > > generally done by using the conditional content mechanisms of a
> > > markup language.
> > >
> > > Thanks!
> > >
> > > - Eric
> > >
> > > Old defintion of "Optional content" per
> > > http://lists.w3.org/Archives/Public/w3c-wai-ua/2001JanMar/0249.html
> > >
> > > -------------------------------------------------
> > > Part III: Definition of optional content
> > > -------------------------------------------------
> > >
> > > Optional content is content that the author does not intend the
> > > user agent to render by default, but that the author does intend
> > > to make available to the user through the user interface under
> > > certain conditions. Some mechanisms for providing optional
> > > content include the "alt" attribute and the OBJECT element in
> > > HTML, and the test attributes of SMIL 1.0 and SMIL 2.0.
> > >
> > > The rendering semantics (when and where) of optional content may
> > > be well-defined in some cases (e.g., "alt" and OBJECT in HTML)
> > > and less well-defined in others (e.g., "title" in HTML).
> > >
> > > Note: The Web Content Accessibility Guidelines 1.0 requires that
> > > authors provide text equivalents for non text content. This is
> > > generally done by using the optional content mechanisms of a
> > > markup language.
> > >
> > > > -----Original Message-----
> > > > From: oedipus@hicom.net [mailto:oedipus@hicom.net]
> > > > Sent: Thursday, February 22, 2001 4:58 PM
> > > > To: w3c-wai-ua@w3.org
> > > > Subject: Conditional versus Optional: Preliminary Observations
> > > >
> > > >
> > > > Conditional versus Optional: Preliminary Observations
> > > >
> > > > in the minutes from the 22 February 2001 telecon
> > [reference 1], the
> > > > following exchange was recorded:
> > > >
> > > > quote
> > > >   GR: "Required optional content" is a little weird.
> > > >
> > > >   IJ: Good point!
> > > >
> > > >   Action IJ: Find clearer wording.
> > > >
> > > >   GR: I propose changing "optional content" to
> > "conditional content".
> > > >       I think that conditional doesn't presume that one form of
> > > >       content is preferred over another.
> > > >
> > > >   IJ: I don't think "optional" suggests that optional content
> > > >       is lower class.
> > > > unquote
> > > >
> > > > 1. required bits are not "optional"--"required optional" is an
> > > > oxymoron; what is "optional" is the discretionary portion of
> > > > the requirement--for example, in the HTML4/XHTML world, deciding
> > > > on appropriate ALT text for the IMG element...  the A, the L,
> > > > the T, the equals sign, and a pair of quotes are required--what
> > > > goes between the quotes is the optional bit...
> > > >
> > > > 2. "conditional" because what is delivered to the requesting UA
> > > > is the derivative of the conditions surrounding slash containing
> > > > slash initiating the transaction; moreover, the conditions under
> > > > which content is delivered (or in which content is capable of
> > > > being delivered) are not always/necessarily "optional", as they
> > > > may (or are quite likely to) include both those over which the
> > > > user has either no or limited control, or of which the user is
> > > > ignorant (in a non-pejorative sense)--conditions can also be
> > > > predicated upon explicit user choice; server side filters and
> > > > transformations, including processing by proxy servers;
> > > > configurations slash settings; hardware limitations; language
> > > > preference (accept) settings; functional limitations,
> > > > environmental limitations; markup support slash standards
> > > > compliance ; etc.; the point is that the "content" (the message)
> > > > is capable of being delivered by a number of potential messengers
> > > > (content/file types), depending upon which is most appropriate--
> > > > e.g. when certain conditions (no matter their source) apply, send
> > > > slash receive slash expose slash render X, not Y or Z, but if X
> > > > does not exist slash has not been provided, Q will be
> > acceptable...
> > > >
> > > > 3. "conditional" is completely neutral--no need to speak of
> > > > equivalencies; doesn't champion slash pit one form of content
> > > > slash modality over another, as it doesn't matter why the
> > > > conditions exist, only that the UA respond to them
> > > > appropriately, by providing content in the most appropriate
> > > > content-type slash form slash modality, whether due to an
> > > > explicit request for a particular content type, the explicit
> > > > exclusion of unsupported slash unusable slash unwanted content
> > > > types, or by preference slash cascade order
> > > >
> > > > 4. the term "conditional" captures the nuances of the term far
> > > > more concretely, and far less ambiguously, than "optional", as
> > > > it incorporates user configuration; negotiation transactions
> > > > (such as those based on CC/PP, accept headers, etc.); SWITCH-
> > > > and SWITCH-like mechanisms; the rendering order of nested
> > > > OBJECT elements; SMIL test attributes; and the CSS cascade, to
> > > > name but a few
> > > >
> > > > 5. "optional" is a dangerous term because the plain English
> > > > language definition of the word "optional" is, according to
> > > > the online edition of Webster's (http://www.m-w.com)
> > > >
> > > > quote
> > > >   involving an option : not compulsory
> > > > unquote
> > > >
> > > > which (at least to my ears) eliminates the term from contention,
> > > > as use of the ALT attribute for the IMG element is compulsory in
> > > > HTML4/XHTML1...
> > > >
> > > > gregory.
> > > >
> > > > PS: i know that the example is technology-specific, but that's
> > > > simply because the case of IMG is the most familiar and clearest
> > > > illustration of the point...
> > > >
> > > > References:
> > > >
> > > > [1] (long URI warning!)
> > > >
> > http://lists.w3.org/Archives/Public/w3c-wai-ua/2001JanMar/0258.html
> > > > -------------------
> > > > Email sent using AnyEmail from http://www.hicom.net
> > > >
> > >
> >

Jon Gunderson, Ph.D., ATP
Coordinator of Assistive Communication and Information Technology
Division of Rehabilitation - Education Services
MC-574
College of Applied Life Studies
University of Illinois at Urbana/Champaign
1207 S. Oak Street, Champaign, IL  61820

Voice: (217) 244-5870
Fax: (217) 333-0248

E-mail: jongund@uiuc.edu

WWW: http://www.staff.uiuc.edu/~jongund
WWW: http://www.w3.org/wai/ua
Received on Friday, 23 February 2001 13:37:32 UTC

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