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Re: Technique for Attribute Access

From: Jon Gunderson <jongund@staff.uiuc.edu>
Date: Thu, 06 May 1999 09:31:32 -0500
Message-Id: <199905061426.JAA19289@staff2.cso.uiuc.edu>
To: Harvey Bingham <hbingham@ACM.org>, w3c-wai-ua@w3.org
Thanks for the quick posting Harvey.  

Could we change the name of the checkpoint to:
Checkpoint: Allow the user to search for an element by its attribute values
Subgroup: dependent user agents
Priority: 3

At 05:57 PM 5/5/99 -0400, you wrote:
>Per our discussion today, here's a possible checkpoint and technique.
>Checkpoint: Allow the user to learn of attributename="value" pairs for any
>Priority: 3
>The meta-information about an element contained in attribute values can 
>support the understanding of the containing element, or its descendents.
>It should be exposable by user request.
>Many attributes are implicitly present, so the presence in an element of an 
>attribute=value pair cannot be depended upon for information. It is up to
>semantic description of each attribute name and its allowed values for an 
>element type to indicate both the explicit meaning of the attribute, and
>is the defaulting meaning of a missing attribute. Often this meaning can be 
>determined from the value of the same-named attribute on an ancestor element.
>Other times the semantics indicate no inheritance (e.g., an id, a document-
>unique identifier for referencing a particular element). 
>Some attributes are generally applicable to all or most element types. For 
>these, common understanding of their use is reasonable to expect for authors 
>and users. 
>Search on attributename and possibly value is important. Search may be on 
>the next attributename, or on attribute value, possibly inherited, possibly 
>qualified by element name. 
>Each search returns the next occurrence of the containing element. An 
>implementation possibility is to list all matches, and return them in 
>order to the user.
>Another useful result is to learn the different attributename="value" pairs 
>or a subset of them for any particular element.
>Another useful search is to find the next element that can have a particular 
>attributename, and for it seeking its default value, possibly from the 
>nearest ancestor.
>Details for HTML 4.0: These common attributes are associated with almost 
>all HTML 4.0 element types, and can be learned: 
>% attrs
>  "%coreattrs; %i18n; %events;"
>% coreattrs
> "id          ID             #IMPLIED -- document-wide unique id --
>  class       CDATA          #IMPLIED -- space separated list of classes --
>  style       %StyleSheet;   #IMPLIED -- associated style info --
>    ELEMENT TYPES WITHOUT %attrs; but with %coreattrs
>        BDR  -- bi-directional override--
>        BR   -- forced line break --
>        HR   -- horizontal rule --
>% i18n
>  lang        %LanguageCode; #IMPLIED -- language code --
>  dir         (ltr|rtl)      #IMPLIED -- direction for weak/neutral text --"
>    ELEMENT TYPES WITHOUT %attrs; but with %i18n; 
>        HTML, HEAD   -- lang, dir defaults for document --
>        META, TITLE  -- lang, dir, for use with content --
>        STYLE        -- lang, dir, for use with title in HEAD --
>% events;
> "onclick     %Script;       #IMPLIED -- a pointer button was clicked --
>  ondblclick  %Script;       #IMPLIED -- a pointer button was double
>  onmousedown %Script;       #IMPLIED -- a pointer button was pressed down --
>  onmouseup   %Script;       #IMPLIED -- a pointer button was released --
>  onmouseover %Script;       #IMPLIED -- a pointer was moved onto --
>  onmousemove %Script;       #IMPLIED -- a pointer was moved within --
>  onmouseout  %Script;       #IMPLIED -- a pointer was moved away --
>  onkeypress  %Script;       #IMPLIED -- a key was pressed and released --
>  onkeydown   %Script;       #IMPLIED -- a key was pressed down --
>  onkeyup     %Script;       #IMPLIED -- a key was released --"
>    ELEMENT type without %attrs; but with %events; (and %coreatts;)
>        HR -- horizontal rule, takes space, has no text --
>    ELEMENT types with none of %attrs;, %coreatts;, %i18n;, or %events;
>        PARAM
>        BASE
>        SCRIPT
>Some attribute names are used in consistent ways, as reflected by their
comments. A few seem
>to have different semantics. The latter should be avoided, particularly
where inheritance
>of attribute value is presumed.
>For XML applications, a similar set of general attributes may be useful. A
common occurrence
>is to specialize a general element name to indicate a local variation on
the general
>element type. For example, in electronic books, different books have
different names for
>the hierarchic sectioning. Some use chapter, some use part, some use
section, some use "El Parto".
>Regards/Harvey Bingham
Jon Gunderson, Ph.D., ATP
Coordinator of Assistive Communication and Information Technology
Division of Rehabilitation - Education Services
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
Received on Thursday, 6 May 1999 10:26:15 UTC

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