World Wide Web Consortium (W3C)
"Leading the Web to its full potential"
- International, vendor-neutral consortium
- Multi-stakeholder, consensus process
- Open and royalty-free Web standards:
- HTML, CSS, XML, SVG, SMIL, ...
Web Accessibility
The power of the Web is in its universality. Access by everyone regardless of disability is an essential aspect. - Tim Berners-Lee, February 1997
Web Accessibility Initiative (WAI)
Operates fully under the W3C Process:
- Accessibility support in W3C technologies
- Guidelines for implementing accessibility
- Methods for evaluating accessibility
- Conducting education and outreach
- Coordinating with Research & Development
Components of Web Accessibility
WCAG 2.0 - Objectives
Web Content Accessibility Guidelines (WCAG) 2.0
- W3C Web standard since 11 December 2008
- Technology-independent
- Objectively testable
- Flexible for situations
- Support for developers
WCAG 2.0 - Documents
WCAG 2.0 - Structure
- Principles (4)
- Guidelines (12)
- Success Criteria - Level A (25)
- Success Criteria - Level AA (13)
- Success Criteria - Level AAA (23)
- Conformance
Note: WCAG 1.0 had 14 Guidelines and 65 Checkpoints
WCAG 2.0 - Principles
"POUR accessibility with WCAG 2.0":
- Perceivable
- Operable
- Understandable
- Robust
WCAG 2.0 - Guidelines
Examples of WCAG 2.0 Guidelines:
WCAG 2.0 - Success Criteria
Examples of WCAG 2.0 Success Criteria:
- 2.1.3 Keyboard (No Exception): All functionality of the content is operable through a keyboard interface without requiring specific timings for individual keystrokes - Level AAA
- 3.3.1 Error Identification: If an input error is automatically detected, the item that is in error is identified and the error is described to the user in text - Level A
WCAG 2.0 - Conformance
Defines meaning of conforming to WCAG 2.0:
- Conformance Levels
- Full Web pages
- Complete processes
- Non-interference
- Conformance claims
- Partial conformance
WCAG 2.0 - Documents
WCAG 2.0 Techniques
Techniques are published as a "W3C Working Group Note":
- Sufficient Techniques - minimum requirements
- Advisory Techniques - additional improvements
- Common Failures - often encountered mistakes
WCAG 2.0 Techniques - Situations
1.1.1 Non-text Content: All non-text content that is presented to the user has a text alternative that serves the equivalent purpose - Level A:
- A: If a short description can serve the same purpose
- B: If a short description can not serve the same purpose
- C: If non-text content is a control or accepts user input
- D: If non-text content is time-based media (or sensory)
- E: If non-text content is a CAPTCHA (or test)
- F: If non-text content should be ignored by assistive tech
WCAG 2.0 Techniques - Contents
Techniques provide technology-specific implementation guidance:
- Applicability
- Description
- Examples
- Resources
- Related Techniques
- Tests
WCAG 2.0 Techniques - Tests
Example Technique - H36 - Using alt attributes on images used as submit buttons:
- Procedure
- For all input elements that have a type attribute value of "image", check for the presence of an alt attribute.
- Check that the alt attribute indicates the button's function.
- Expected Results
- #1 und #2 are true
WCAG 2.0 - Documents
Understanding WCAG 2.0
Understanding WCAG 2.0 provides context-sensitive information:
- Intent
- Benefits to people with disabilities
- Example scenarios
- Resources
- Related Techniques
WCAG 2.0 - Documents
WCAG 2.0 - Quick Reference
WCAG 2.0 - Dynamic Checklist
Testable Requirements
Comparison of color-contrast approaches:
Technological Improvements
Better addresses areas such as:
- Web Technologies
- Mulitmedia contents
- Web applications
- Natural language
- Complete processes
Comprehensive Guidance
Documentation for WCAG 2.0 provides support:
- Web has become complex and so has accessibility
- Documented techniques help implement WCAG 2.0
- Background information helps developer learn
- Material can be catered to the developer needs
User-Centered Design
WCAG 2.0 well fits into usability processes:
- Many possibilities to achieve a purpose
- Developer selects appropriate solutions
- Supports testing with users for analysis
- Guidance on optimization beyond minimum
Transitioning Support
Some WAI resources to help support transitioning:
