W3 C Specification For Interoperability And Accessibility For Ajax, Dhtml, Xml Etc Based On Rdf Taxonomy

ARIA Lisa Seeman, W3C invited expert W3C specification for interoperability and accessibility for AJAX, DHTML, XML Etc… Based on RDF Taxonomy

Contents
Making it Simple – an XML Specification
Getting started
The problems; the solution
Background technology
A solution
More detailed
Focus
Relationships
RDF
The RDF Specification
Extending roles
Why RDF
Ask Questions Don’t let it go too fast

Contents
Getting started
A solution
More detailed
Focus
Relationships
RDF
Extending Roles
Why RDF

What is the Problem?
Why can’t users with disabilities/ unusual device access all websites?
If content and functionality assume a screen and a mouse
No use of images without proper definition and clarification Old Alt tag static Use headers (H1..) Avoid use of scripts No use of “normal” multimedia/Flash
New
Add semantics (
S tructure,
Role
state
Make focus keep with flow of the page
Keep elements inside of the DOM

Problems with DHTML
Lack of knowledge, lack of Semantics
What things are
What they are doing
What the relationships are
Focus

How Accessibility Works

Accessible Tree - Firefox
Subset of the DOM tree
<table> <html> <td> # text <p> <a> <i> #text <td> #text
Exposed as MSAA or ATK
Name: e.g. “click here”
Role: ROLE_LINK
States:
STATE_FOCUSABLE |
STATE_FOCUSED |
STATE_LINKED |
STATE_TRAVERSED
#text < div > #text <div role=“”> <tbody> <tr> #text

To Summarize the Problem
We Need Semantics !!!!!
Let us know what we have and what is happening

Contents
Getting started
A solution
More detailed
Focus
Relationships
RDF
Extending roles
Why RDF

Core Concepts – Semantic Web
Additional layers of information
Meaning to terms
Links to relevant information
Links to relevant people
Allow software agents to manipulate this information
Ontology defines terms

Simplified RDF
<RDF> <Description about="http://www.ubaccess.com/SWAP">
<author>Lisa</author>
<updated datatype=“year”>2006</updated> </Description>
</RDF>
http://www.ubaccess.com/SWAP author Lisa
http://www.ubaccess.com/SWAP updated 2006
SWAP Author Lisa

Core Concepts – RDF
RDF is a protocol of the semantic web
Uses graph logic
Intelligent semantics
Define terms
Define relationships
Make statements
Make inferences

Contents
Getting started
A solution
More detailed
Focus
Relationships
RDF
Extending roles
Why RDF

ARIA Taxonomies
Roles can be used to build accessible applications by providing any missing information that the assistive technology needs to anticipate the behavior of the elements inside the application.
For example, to support accessibility the browser may create accessible objects of a web page though the Accessibility API of the operating system. When the full semantics are provided and understood by the browser, the application will properly map the page to accessible objects of the operating system.

Roles
What the thing is
Things that do not change in a session
Uses RDF to describe relationships
Example: This is a checkbox
RDF: A check box is a form of select, can be checked, etc…

Relationships
Why are relationships important?
What it is
describedby , labeledby
Hierarchical
Haspopup
Control
Flow
Group structure
Tree, group, region (roles)

States and Author-Settable Properties
Things that can change in the session
System and author changeable
Changes in state
User changeable

Roles and States, Examples
Role is a …. tree group, tree item, Grid, checkbox
And is labeledby, flowto, controls,
And live ....
State … Checked, pressed, value, selected

How Accessibility Works

How does that help?
Roles:
Map to the right MSAA object ( ROLE_MENUITEM or ROLE_LINK)
And to right states (STATE_FOCUSABLE, STATE_CHECKABLE)
States and properties: Scripts activate on toggled states that AT can understand and respond to. It exposes the state information. AT can know what is going on and can tell user
valuenow maps to EVENT_VALUE_CHANGE
aria-checked aria-expanded aria-readonly
aria-disabled maps to EVENT_STATE_CHANGE aria-required aria-invalid
aria-describedby

A Simple Example
<?xml version="1.1" encoding="us-ascii"?>
<!DOCTYPE html PUBLIC "Accessible Adaptive Applications//EN" http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html lang="en"> <head> <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> </head>
<body>
<p>Here's a checkbox that you can click on.</p>
<div> <span class="checkbox" id="chbox1" role="checkbox" aria-checked="true" onkeydown="return checkBoxEvent(event);" onclick="return checkBoxEvent(event);" > Include decorative fruit basket </span> </div>
</body>
</html>

Contents
Getting started
A simple example
More detailed
Focus
Relationships
RDF
Extending roles
Why RDF

Focus
Choices for elements normally not focusable:
Tab key focusable tabindex >= “0”
Script - or click - only tabindex <= “-1”
Not focusable default / no tabindex
Works with flowTo

Building Accessible Applications
Step 1: Use your native mark up as well as you can
Step 2: Find the right roles
Set roles to make sure elements behave predictably and correctly describes the behavior of each element within your application (unless elements behaviors are fully described by the native markup language).
Step 3: Look for groups
Look for groups within a page, and mark them using the most appropriate role that best describes their usage.
Step 4: Build relationships
Sometimes the relationships can be made clear via the native mark up language.
Sometimes this can be implied via the DOM.
In other cases, use the States and Properties. For example: aaa:property in region B to reference region A.
Step 5: Set properties
Set properties until the behavior of the element is defined and described (such as aaa:required aaa:live)
Control the behavior of the element using device independent events, states, and properties.
Set Focus

Contents
Getting started
A simple example
More detailed
Focus
Relationships
RDF
Extending roles
Why RDF

RDF owl:ObjectProperty
<owl:ObjectProperty rdf:ID=" mustContain "> <rdfs:comment xml:lang="en">A child that must be contained by this role</rdfs:comment> <rdfs:subpropertyOf rdf:resource="#scope"/> </owl:ObjectProperty>
<owl:ObjectProperty rdf:ID=" supportedState "> <rdfs:comment xml:lang="en">A state that can be supported for this Role</rdfs:comment> <rdfs:domain rdf:resource="#roletype"/> </owl:ObjectProperty>
<owl:ObjectProperty rdf:ID=" requiredState "> <rdfs:comment xml:lang="en">A state that must be provided for this Role</rdfs:comment> <rdfs:subpropertyOf rdf:resource="#supportedState"/> <rdfs:domain rdf:re source="#roletype"/> </owl:ObjectProperty>

RDF - Using Properties in owl:Class
<owl:Class rdf:ID="combobox">
<rdfs:subClassOf rdf:resource="#select"/>
<rdfs:seeAlso rdf:resource="http://www.w3.org/TR/html401/interact/forms.html#edef-SELECT"/>
<rdfs:seeAlso rdf:resource="http://www.w3.org/TR/2007/REC-xforms-20071029/#ui-selectMany"/>
<role:nameFrom>author</role:nameFrom>
………
< role:mustContain rdf:resource="#listbox"/>
< role:mustContain rdf:resource="#textbox"/>
< role:supportedState rdf:resource="http://www.w3.org/2005/07/aaa#aria-required"/>
< role:requiredState rdf:resource="http://www.w3.org/2005/07/aaa#aria-expanded"/>
</owl:Class>

Base Class
<owl:Class rdf:ID="roletype">
<rdfs:subClassOf> <owl:Restriction> <owl:onProperty rdf:resource="http://dublincore.org/2003/03/24/dces#description"/> <owl:cardinality rdf:datatype="http://www.w3.org/2001/XMLSchema#string">1</owl:cardinality> </owl:Restriction> </rdfs:subClassOf>
…… ..
<role:supportedState rdf:resource="http://www.w3.org/2005/07/aaa# aria-controls "/>
<role:supportedState rdf:resource="http://www.w3.org/2005/07/aaa# aria-describedby "/>
<role:supportedState rdf:resource="http://www.w3.org/2005/07/aaa# aria-disabled "/>
<role:supportedState rdf:resource="http://www.w3.org/2005/07/aaa# aria-dropeffect "/>
<role:supportedState rdf:resource="http://www.w3.org/2005/07/aaa# aria-flowto "/>
<role:supportedState rdf:resource="http://www.w3.org/2005/07/aaa# aria-grabbed "/>
<role:supportedState rdf:resource="http://www.w3.org/2005/07/aaa#a ria-labe l"/>
<role:supportedState rdf:resource="http://www.w3.org/2005/07/aaa# aria-labelledby "/>
<role:supportedState rdf:resource="http://www.w3.org/2005/07/aaa# aria-live "/>
<role:supportedState rdf:resource="http://www.w3.org/2005/07/aaa# aria-owns "/>
…… .
</owl:Class>

A Simple Example
Web Page
<body>
<p>Here's a checkbox that you can click on.</p>
<div> < span class="checkbox" id="chbox1" role="checkbox"
aria-checked="true" onkeydown="return checkBoxEvent(event);" onclick="return checkBoxEvent(event);" > Include decorative fruit basket </span> </div>
</body>
Schema <owl:Class rdf:ID="checkbox"> <rdfs:subClassOf rdf:resource="#input"/> …..<role:requiredState rdf:resource="http://www.w3.org/2005/07/aaa#aria-checked"/> </owl:Class>

Contents
Getting started
A simple example
More detailed
Focus
Relationships
RDF
Extending roles
Why RDF

How to Extend
Choose sensible inheritance
Provide a title and description for your role
Ensure that all supported states are explicit
Define the anticipated content and scope of the role
Define any related concepts
Set defaults when appropriate
Example:
…… Compare to making accessible applications

Using Datatype and Groups Group container labeled “ date chooser” Contains combobox labeled day Datatype =Day Contains combobox labeled month Datatype = Month Contains combobox labeled year Datatype = gyear

Extend Roles If …
Groups, a title and description will not complete the missing information, such as supported states.
Need to define composite roles
Need to define more nodes (states, roles) or relationships
Understand RDF over UML
Cost = support and complexity, performance
Do you best to overcome barriers to entry

Contents
Getting started
A simple example
More detailed
Focus
Relationships
RDF
Extending roles
Why RDF

Why you might use RDF …
You need best knowledge - Life is a graph not a tree
You don’t know what question will be asked in the future – Infer, not access
Your structure can evolve - New type of properties, New types of nodes
You might not think of everything - Like me
RDF comes naturally (Graphs and relationships not just trees and hierarchy !!!!)

Required Office Interactions Programmer 1 Accounts Programmer 1 Product manager CEO Account manager Office manager Project manager

Why RDF - Revisited
Life is not neat
Life is informal
Better relationships better knowledge more power
Better evolve-ability better knowledge
The real world is a graph not a tree
Warning: Barrier to entry, performance
(our solution – keep simple things simple)

To Conclude
See:
http://www.w3.org/TR/wai-aria/
http://www.w3.org/TR/wai-aria/rdf_model
www.w3.org/TR/rdf-primer/
Any other questions? lisaEseeman@gmail.com
Thank You

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W3 C Specification For Interoperability And Accessibility For Ajax, Dhtml, Xml Etc Based On Rdf Taxonomy

by Israeli Internet Association technology committee on Feb 04, 2010

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W3 C Specification For Interoperability And Accessibility For Ajax, Dhtml, Xml Etc Based On Rdf Taxonomy — Presentation Transcript