- From: Al Gilman <Alfred.S.Gilman@IEEE.org>
- Date: Fri, 27 Jan 2006 14:18:07 -0500
- To: public-cdf@w3.org
- Cc: wai-liaison@w3.org
<note
class="inTransmittal">
These comments have been collected and lightly reviewed within the
User Agent Working Group and the Protocols and Formats Working Group.
Where they are not clear or you feel you need to reject a comment, we
would welcome the opportunity to discuss the issues for the purposes
of clarification and mutual understanding.
Thanks,
Al
/chair, PFWG
</note>
CDF 1.0 review
Sounds like are requiring DOM 3 through the use of ReferencedDocument
- Document.Write() is gone - yes?
Are you going to get the browser manufacturers to implement this as
none of the support DOM 3 today? DOM 3 has accessibility features.
Section 2.2. You indicate that a child document may allow for event
propogation up. You may want for selective propogation. Implementing
Dynamic XHTML accessibility solutions usually involves placing a
keyboard handler on the root document to capture all the keyboard
commands and driving navigation. You would like to have this drive
navigation of all child documents as well instead of having this in
multiple interception points. The group should consider that
DocumentEventPropagation be selective. You may not want all events to
propoagate up. Your interface, below, indicates a boolean decision
for all events:
interface DocumentEventPropagation {
attribute boolean propagate;
};
How do you deal with tab sequencing? Each document may have a
different tabbing mechanism such as XHTML 1.X using TABINDEX and
XHTML 2.0 using nextFocus.
What is the default language per embedded document? For example, what
happens when you have a lang attribute in a block, specified in
XHTML, set to Spanish, and within it you have an object tag
referencing an embedded SVG document or some other document? XHTML
2.0 requires a lang attribute on the document. It would be nice if we
stressed consistency across other XML markups - or we require this on
the object tag.
Section 2.3.1
Why do you refer to HTML4 in this spec. No HTML 4 implementation
supports DOM 3. Also it is non-extensible which is problematic for
adding accessibility semantics targeted for XML markup.This ius a
step backward. It would seem that supporting an non-XML based infoset
document format is a mistake.
2.1.4 SecurityException
http://www.w3.org/TR/2005/WD-CDR-20051219/#security-exception
Accessing parent or child documents through the DOM as described in sections
2.1.2 and 2.1.3 can be disabled for security reasons. In such cases user
agents should throw a SecurityException
<UAWG> User agents should inform the user that access has been blocked for
security reasons.
</UAWG>
2.3 Link Activation
http://www.w3.org/TR/2005/WD-CDR-20051219/#link-activation
<snip>
Nested hyperlinks are more complicated. The following illustrates nested
hyperlinks. Suppose the parent document is XHTML as follows:
<!-- parent.html -->
<html:a href="LargeMap.html">
<html:object type="image/svg+xml" data="child.svg"/>
</html:a>
And the child SVG document contains the following:
<!-- child.svg -->
<svg:a xlink:href="DetailedCountyMap.html">
<svg:text>county map</svg:text>
</svg:a>
<snip>
The implication is that the behavior of nested hyperlinks depends on how the
hyperlink is activated. Here are some examples which illustrate common
possibilities:
* Suppose the user gives focus to an <html:a> within the parent XHTML
document above and then hits the "Enter" key to activate that link. In the
example above, the <html:a> element is the event target. This would cause
execution of the hyperlink to "LargeMap.html".
* Suppose the user gives focus to an <svg:a> within the child SVG document
and then hits the "Enter" key to activate that link. In the example above,
the <svg:a> element is the event target. This would cause execution of the
hyperlink to "DetailedCountyMap.html".
* Suppose the user uses a mouse or other pointer device to click on the work
"county map" in the above example. Because this pointing device event occurs
over geometry controlled by both the parent XHTML and child SVG documents,
and because the SVG document is the most deeply nested, then the target
element will be chosen according to the rules in the SVG specification. In
the example above, this will cause the <svg:text> element to be the event
target. The <svg:a> element will receive the event after bubbling from the
<svg:text> element, which will cause a hyperlink to
"DetailedCountyMap.html".
<UAWG>The above scenario provides some intriguing accessibility problems. At
each stage the user must be given a choice 1) activate the anchor, 2) enter
the nested container. The user agent must inform the user of the available
paths, so the user is able to give focus to the required element.
Given the first 2 bullets in the scenario, the user agent will display the
text "county map" with html anchor designation (blue and underlined,
assuming no style sheet). When the user gives focus to the anchor "county
map", the user agent should inform the user that a hyperlink may be
activated or a child container may be entered. The user now has the option
of viewing "LargeMap.htm" or entering the "child.svg" container. After
entering the "child.svg" container can the user be informed that an
additional anchor (svg:a) is available to be given focus and execution to
display "DetailedCountyMap.htm" (the second bullet). At any point in the
tree the user (with information available from the user agent) should be
able to orient themselves (determine where they are) within the document(s)
tree (parent document - html:a - child.svg - svg:a) and navigate back up or
down the tree.
The 3rd bullet "* Suppose the user uses a mouse or other pointer device to
click on the work "county map" in the above example. Because this pointing
device event occurs over geometry controlled by both the parent XHTML and
child SVG documents, and because the SVG document is the most deeply nested,
then the target element will be chosen according to the rules in the SVG
specification. In the example above, this will cause the <svg:text> element
to be the event target. The <svg:a> element will receive the event after
bubbling from the <svg:text> element, which will cause a hyperlink to
"DetailedCountyMap.html".
Question: How will a pointing device user able to activate the html:a
"LargeMap.html"? or Where in the geometry does one point to activate the
html:a "LargeMap.html"? How is the user agent to inform the user that two
(or possibly more) paths are available from a single (visually apparent)
anchor?
</UAWG>
Web Integration Compound Documents (WICD Core) review
Commenting on http://www.w3.org/TR/2005/WD-WICD-20051219/
3.2.1 Why would you not allow for a link to be activate on a static
rendering. Image maps allow for links on static elements? They in
themselves are not dynamic but they tell the browser where to go.
When you traverse the content within an static svg document, will
there still be a DOM for the SVG document? Is the DOM gone such that
you cannot walk the children. You are not explicit here. Remember,
script writers may want to walk it. The difference is that the DOM
elements in the SVG will have handlers that do not work.
Whether static or frozen, why would you not want the links to be
activatable. AT vendors would walk the DOM and want to activate the
link. Is the memory reclamation for links that valuable. If you are
going to do this then more work to address state changes of frozen
and static so that AT vendors can monitor when links become active or
disabled.
3.2.2 Scalable Background Image
This document should state that background images MUST not convey any
useful information. In other words they must only be eye candy. They
must always be fixed. Low vision users, in particular seniors, will
want to remove these images as they will not be able to read text in
a document. Others will want to programatically disable the animation.
3.2.3 Scalable Overlay Objects (Sprites)
This is a potential accessibility problem. If the Overlay is an SVG
document, the user needs to be able to navigate it. How, through the
DOM does a scripting application or user agent travers the overlay
and come back? What semantics in the DOM indicate an overlay or a
real active document?
3.3.3 Transparency
This is potentially an accessibility problem. If something is an
overlay it must be possible to give something in the overlay focus.
For example, you could have an xhtml menu and then launch a sub menu
in SVG. Now, when it comes to these issues it tells me you also need
to accomodate the work we are doing in WAI PF to address
accessibility for roles, properties, and states. Associations need to
be made between related objects once you put them outside the
confines of a boxed area on the page.
6 Focus Support
This is inadequate.
- How does one navigate in and out of a child document when TABINDEX
is applied in the XHTML root and the embedded object is SVG? How does
this impact the tab sequence when the embedded document uses
something other than TABINDEX?
- When someone is tabbing in a document, what is the navigation
scheme for going into and out of an embedded document. Do you tab
into the document, tab out, what? Does the user agent have to provide
additional keys.
There is more here than just being able to give an object focus. You
need to decide for the author how navigation will work in and out of
a compound document. This is a problem today for plug-ins where often
there is no mechanism to use the keyboard to step into a plug-in and
out. This document adds an additional level of extraction because
documents are linked together in that you can navigate up to and into
referenced DOMs. If this is the case, then how is navigation
addressed consistently.
6.1 Focusable Child Elements
Comments here are not CDF issues but the inconsistency in document
focus support. The focusable property, while available in SVG, is
incosistent with XHTML. I would like to see the addition of TABINDEX,
as implemented in IE, addressed for DIVs and SPANs. Note: this could
be an added module.
This means that there needs to be a capabiltiy for any renderable
element in the compound document focusable. The referencing alone is
not a valid reason. In the Dynamic Web Access work
(www.w3.org/wai/pf/adaptable) we can make DIVS and SPANS be focusable
but we do this by placing a TABINDEX on these. TABINDEX can have a
value of 0 (focusable but in document order) or -1 (focusable but
never in the tab order). This is consistent with IE and Firefox.
Note: Progrmatically speaking, an XHTML anchor element has no
property I am aware of that says it has an inherent "focusable"
property. What happens with MathML?
6.2 Focus Event triggered Child Element Animations
In our new DHTML spec you do not need to use anchors - you may also
use divs and spans:
<div TABINDEX= "-1">
<object type="image/svg+xml" data="foo1.svg">
<param name="animation" value="onfocusevent" />
</object>
</div>
It would be good to pull this in.
6.3.1 Two Dimensional Focus Navigation (Flat, Graphical, Joystick)
Accessibility requires logical navigation. You need solid rules for
determining navigation. Viscinity navigation seems silly and in fact
it looks like you skip elements that should be traversable. Although
this section is informative, what if I have a declarative tabindex
solution - would this take precedence?
To point out applicable parts of your this section:
The focus navigation algorithm consists of three phases: finding
candidates for focus movements, calculating and adjusting movement
based on a distance function, and moving the current focus point with
possibly changing focusable element.
- Navigation should be logical determined by document structure, or
specified by the author
- Requiring the user to follow navigation to all elements in a series
without a consistent mechanism to compartmetalize and skip sections
(like menus in a GUI) is a usability problem.
This viscinity navigation approach should go away over time.
6.3.2 One Dimensional Focus Navigation (Linear, Focus Ring, Tab)
This is frought with usability problems. New DHTML work will allow
you to skip to content without of semantic interest without tabbing
through every element. (DHTML work). XHTML can skip this standard
navigation by using Keyboard handlers and JavaScript. Got to this
URL:
<http://www.mozilla.org/access/dhtml/spreadsheet>http://www.mozilla.org/access/dhtml/spreadsheet
This is very stressful for people with mobility impairements and
people who are blind. The user is being made to traverse all elements
whether needed or not. Although this section is informative, what if
I have a declarative tabindex solution - would this take precedence.
7.1 System Fonts
System fonts must be supported by the operating system such that when
their sizes are changed by the user they are reflected on the
document. This impacts Font Sharing - I believe but that is not clear.
This is not a CDF issue but it is important that this be stated.
9.2.1 Interaction with the 'render' param
User agents must allow others to change the rendering speed. High
rendering rates (flashing) can cause seizures for people with
epilepsy.
<http://www.w3.org/TR/2005/WD-WCAG20-20051123/guidelines.html#seizure>http://www.w3.org/TR/2005/WD-WCAG20-20051123/guidelines.html#seizure
CDF should require the user agent who is implementing this to
configure the rate of animation.
9.3 Play Animations while Document is loading
There is a problem when network latency and bit-heavy sub-objects
cause the onLoad event
to fire after the user has started to interact with widgets in the page.
http://hades.mn.aptest.com/cgi-bin/xhtml2-issues/HyperAttrs?id=7792
PFWG would like to confirm that this is a serious and common problem.
The current suggested remedy from PFWG to the HTML WG is that
<quote
cite="http://www.w3.org/2006/01/25-pf-irc#T14-43-18 ">
an onload script handler attempting to set focus after focus has
already been set should cause the user agent to generate an exception
to the script being executed and not move focus.
</quote>
Please continue to track this issue to its resolution.
1.1 Scope - http://www.w3.org/TR/2005/WD-WICD-20051219/#scope
In the description of the profiles the following items are listed:
1 Content author/provider has exact control of the presentation, including
fonts, layout, color, etc.
2 Layout adaptation: layout can be based upon device characteristics -
screen size, color depth, resolution, orientation.
3 Presentation can be customized to reflect a brand or user's personality.
<uawg> first bullet: this can be overridden by the user through system
settings, browser controls, and user css overrides. Correct?
Second bullet: this includes user system settings. Correct?
Third bullet: would like to add “and needs” after “personality”
</uawg>
3. Scalable Child Elements
http://www.w3.org/TR/2005/WD-WICD-20051219/#scalable-child-formats
<uawg>
We agree with the requirements for functions user agents must support.
On reading this section, we hoped to find something about the user being
able to scale the destination box.
For example: a user has default font size set to 18 points. An svg element
with fixed size (100x100) is referenced in a document. The default font size
causes the information to expand behind the bounding edge of the svg
element. The user must now focus on the svg and scroll within the svg.
</uawg>
6.1 Focusable Child Elements
http://www.w3.org/TR/2005/WD-WICD-20051219/#focus-management
<uawg> We agree with the requirements user agents.
“Child-specific functionality should be restricted to preserve the author's
intent. Should element specific functionality be desired, the element must
advertise itself as being focusable or implicitly made focusable by a user
agent.”
There seems to be a conflict here. First you say child-specific
functionality should be restricted. Then, you say “should functionality be
desired, the element must advertise itself as being focusable or implicitly
made focusable by a user agent.” By default the user agent should make all
child elements focusable, so when the user desires specific functionality it
is available. From an accessibility perspective, while the user agent should
respect the author’s intent, the user should be able to override that
intent.
</uawg>
6.3.2 One Dimensional Focus Navigation (Linear, Focus Ring, Tab)
http://www.w3.org/TR/2005/WD-WICD-20051219/#focus-nav-one-dim-linear
<snip>
XHTML and SVG have methods for linear one dimensional focus traversal. XHTML
provides a default traversal order, and allows it to be changed with the use
of tabindex attribute within one XHTML document. SVG's provides the
focusNext and focusPrev elements which may be used to provide similar
functionality within an SVG document. However, neither of these methods can
be used when XHTML and SVG are combined. Therefore in the case of a WICD
document by reference, combining XHTML with SVG, some alternate form of
navigation is required.
<uawg> This is indeed a problem. Perhaps, in a “WICD document by reference,
combining XHTML with SVG”, the user agent should default to one-dimensional
focus transversal based on source code order.
Tabindex and focusNext/focusPrev each have inherent accessibility problems,
mostly confusing the user as to the next/previous element that will receive
focus. Tabindex may take the user on an author defined path through
focusable content and then through the remainder of the focusable content
that was not part of the author defined path. The user can traverse this in
reverse order also, so in this respect it is consistent.
focusNext/focusPrev allows the author to define 2 distinct paths, separate
from the source code order. For example, the content has 6 focusable
elements. Each can have a unique focusNext and a unique focusPrev. In the
list below the first element is the focusable element in source code order,
the second item preceded with an “n” designates the focusNext order, the
third item preceded with a “p” designates the focusPrev order
1 – n2 p6
2 – n4 p3
3 – n1 p5
4 – n3 p2
5 – n6 p1
6 – n5 p4
so following the source path the user would proceed 1-2-3-4-5-6
if the author set focusNext, starting at element 1, the path would be
1-2-4-3-1 and loop from there.
If author set focusPrev, starting at element 1, the path would be
1-6-4-2-3-5-1.
</uawg>
WICD Full 1.0 review
So, why does full only support XHTML 1.1 when your document specifies
the use of XHTML 2 or other markups? Is it because the browser does
not support XHTML 2?
What is most concerning is these specs. address the use of ECMAScript
whose implementation on HTML or XHTML is frought with accessibility
problems due to gaps in HTML. We cannot afford to see this repeated.
This specification misses picking up critical XHTML accessibility
extensions found in XHTML 2 for the role attribute. This WAI PF
working group is also developing (add-ons to XHTML 1.1) to address
dynamic web accessibility (using JavaScript) and they are not being
included here or in the roadmap. This is a big omission. Our changes
can be added onto XHTML 2 so we would like these to be considered for
adding on - otherwise you end up with another scripting accessibility
problem. I would like to see these XHTML 1.1 extensions be
incorporated into these specifications or have a clear migration path
to incorporate them:
<http://www.w3.org/2004/CDF/Group/roadmap.html>http://www.w3.org/2004/CDF/Group/roadmap.html.
The following highlights our specificationss and our roadmap
pertaining to Dynamic Web Access.
Dynamic Web Content Accessibility Work effort:
The working group has a focused effort to fix the accessibility of
Rich Internet web Applications (RIAs). The inaccessibility of these
applications has often been categorized as "JavaScript Accessibility
Problem." These applications make use of script to re-purpose
existing markup to create new application widgets not defined by the
markup. The accessibility of today's markup, such as XHTML and HTML,
depends on the mixture of content and presentation. The accessibility
problem stems from the markup not providing the capability for the
page author to provide additional accessibility Meta data which can
be mapped by the browser to platform accessibility APIs when
re-purposing occurs. The problem surfaces in many other circumstances
ranging from when HTML uses the <table> element for layout to the SVG
usage of primitive drawing markup to create complex graphics that
imply richer semantics. Solving the problem involves the use of
cross-cutting technologies whose principles may be used for
accessibility reform across many industry content renderable markups.
Finally, these specifications are intended to support XHTML markup
rendered in today's desktop browsers. Three W3C WAI PF working drafts
involved are described here:
<http://www.w3.org/WAI/PF/GUI/>Role Taxonomy for Accessible Adaptable
Applications
This specification defines an RDF taxonomy of roles which describe
custom GUI widgets and document structure which may be used to
support platform accessibility APIs. Roles encapsulate semantic
information which may be use to help: user agents support assistive
technologies; authoring tools enforce accessibility, and assistive
technologies discover new custom objects and how to interoperate with
them.
<http://www.w3.org/WAI/PF/adaptable/>States and Properties Module
This specification defines attributes that provide XML languages with
the ability to add extra information about the behavior of an
element. States and Adaptable Properties are mapped to accessibility
frameworks (such as a screen reader) that use this information to
provide alternative access solutions. Similarly state and author
properties can be used to dynamically change the rendering of content
using different style sheet properties. The result is to provide an
interoperable way for associating behaviors with document-level
markup. Additionally, this specification includes markup to fix
keyboard focus problems with today's XHTML 1.X markup.
How the fit into our roadmap:
<http://www.w3.org/WAI/PF/roadmap/>Dynamic Accessible Web Content Roadmap
This roadmap that describes the problem, what W3C specifications will
be used to correct the problem, and the timeline for the new
specifications.
Additionally, this specification does not pick up the standard role
attributes delininiating semantic sections of a document:
<http://hades.mn.aptest.com/htmlwg/xhtml-m12n-2/mod-role.html#s_rolemodule>http://hades.mn.aptest.com/htmlwg/xhtml-m12n-2/mod-role.html#s_rolemodule
WICD Mobile 1.0 review
This calls out for script support and XHTML Basic. XHTML basic does
not support the script and noscript elements. Are you using
ECMAScript to generate the entire page? This is confusing.
The following is from XHTML Basic section 1.3.2. Script and Events
(of XHTML Basic)
The script and noscript elements are not supported. Usually small
devices have limited memory and CPU power. Execution of script
programs may not be supported. Contents should be readable even if
scripts are not executed.
Event handler attributes used to invoke script programs are not
supported. Events are device dependent. An incoming-call event is
unlikely to happen in a television. A generic event handling
mechanism would be more appropriate than hardwiring the event names
in the document type definition.
Rich Schwerdtfeger
Distinguished Engineer, SWG Accessibility Architect/Strategist
Emerging Technologies
Chair, IBM Accessibility Architecture Review Board
blog:
<http://www-106.ibm.com/developerworks/blogs/dw_blog.jspa?blog=441>http://www-106.ibm.com/developerworks/blogs/dw_blog.jspa?blog=441
schwer@us.ibm.com, Phone: 512-838-4593,T/L: 678-4593, mobile: 512-876-9689
"Two roads diverged in a wood, and I -
I took the one less traveled by, and that has made all the difference.", Frost
Received on Friday, 27 January 2006 19:36:32 UTC