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Technological and Evaluation Foundations of Accessible Web
Ossi Nykänen Tampere University of Technology, Department of Mathematics, W3C Finnish Office. A presentation for Media Goes Accessible 19.1.2012, at Aalto University
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Part I: W3C and Web Technologies
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World Wide Web Consortium (W3C)
- Founded in 1994 with the vision of “One Web,” open to all
- Today Web is everywhere
- Web was invented by Sir Tim Berners-Lee, the W3C Director
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…The W3C Open Web Platform
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W3C One Web: Principles and vision
- Web for All
- Web Accessibility Initiative; Internationalization; Mobile Web for Social Development
- Web on Everything
- Web of Devices; Mobile Web Initiative; Browsers and Other Agents
- Web for Rich Interaction
- Web Design and Applications; Web Architecture
- Web of Data and Services
- Essential XML Technologies; Semantic Web; Web of Services
- Web of Trust
- Semantic Web; XML Security, Web of Services Security; Privacy
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What about Web and accessibility?
- Accessibility requires several things, e.g.
- Understanding, willingness, and know-how for supporting true user needs
- Supportive tools and feedback
- Enabling technology incl. open interfaces
- Thus, (Web) accessibility needs to be build into the technologies (and specified in that context)
- Also needed: Active community, best practices, technical guidelines, continuous evaluation, ...
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Part II: Web Accessibility Initiative
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Web Accessibility Initiative
- The W3C Web Accessibility Initiative (WAI) develops strategies, guidelines, and resources to help make the Web accessible to people with disabilities (or context-specific
challenges)
- Launched in 1997, directed by Judy Brewer
- Accessibility built-in for Web technologies
- Guidelines and training materials
- Outreach, projects, ...
- Basis for many regulations
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Web Content Accessibility
- Accessibility is a property of a ”Web page” (incl. apps) that enables successfully using it
- Improve accessibility via four key principles:
- Perceivable
- Operable
- Understandable
- Robust
- ...while paying attention to accessibility issues, perhaps when using assistive technologies
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Interaction of roles and tools is needed
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Pivotal guidelines and techniques
- Standards and documented techniques
- Web Content (WCAG) (also WCAG 2.0 in Finnish)
- Authoring Tool (ATAG); v2.0 in progress
- User Agent (UAAG); v2.0 in progress
- Evaluation Language (EARL); work in progress
- Rich Applications (WAI-ARIA); work in progress
- Also resources for
- Planning, implementing, managing, evaluating, getting involved with WAI, etc.
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Evaluating and reporting accessibility
- Two basic ways of testing:
- Preliminary review
- Conformance evaluation
- Reporting is important
- ”Who, what, criterion, results”
- In the future, reporting can be done in machine-readable exchange format, using the Evaluation and Report Language (EARL)
1.0...
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Part III: Beyond Legacy Assumptions
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What does using an application ”mean”? (Read: We currently spend lot of efforts to describe the graphical user interface...)
- According to a desktop metaphor (”a legacy example”):
- Read instructions, navigate to appropriate view, fill in a visual form fields, click button to submit, read scripted response
(loop)
- Not a disaster if Perceivable, Oper..., Und..., and Ro..., but really:
- From a functional user experience point of view:
- Search information, iterate down to matching functionality, provide task parameters and execute, query results (loop)
- Logically, applications provide information and functions – ”buttons” etc. are part of the user interface implementation
- Tough challenges ahead: Getting overview; naming and matching tasks and functionality; certain kinds of input; remembering
state and history; accessing specific sensory experiences
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Enriching current applications (WAI-ARIA)
- The basic approach for programmatically determining things is to write ”semantics” out (with commonly known model & names)
- A (bad) example of assuming common-sense reasoning:
- User interface: Piece of HTML code (e.g. ”<div>”) is a button if it happens to behave like one (and looks like it)
- From machine-understandable semantic point of view:
- Instead of ”<div>”, say ”<div role='http://www.w3.org/ns/wai-aria/button'>” (i.e. using the standard ARIA taxonomy)
- Even better, anticipate to say ”<button>” in HTML5...
- Result: The Controls of the user interface can be identified
- Perhaps something similar could be applied to functions?
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Enriching evaluation feedback (EARL)
- Integrating and processing narrative eval feedback is tedious – luckily, this can be modelled similarly as well
- A example of assuming common-sense reasoning:
- Report: A report says that the page ”www.example.org” fails to provide alt attributes for images (and hence is not WCAG 2.0-A)
- Considering machine-understandable semantics, say also:
...<earl:Assertion rdf:about="#assertion"><earl:subject rdf:resource="http://www.example.org/"/> <earl:test rdf:resource="http://www.w3.org/TR/WCAG20-TECHS/H36"/> <earl:result rdf:resource="#result"/></earl:Assertion><earl:TestResult rdf:about="#result"> <earl:outcome rdf:resource="http://www.w3.org/ns/earl#failed"/> </earl:TestResult>...
- Result: tests can be integrated and automatically processed
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Fundamental challenges (?)
- Old legacy content and apps
- New applications – and dev tools – are (still) often developed visual design in mind
- Locking applications ”just in case” for business reasons etc. (vs. Open interfaces & linked data)
- New apps, technologies, and devices sometimes re-invent the old (solved?) mistakes
- Everything isn't rocket science, but training is needed; accessibility is also a moving target