WCAG - Web Content Accessibility Guidelines

WCAG – 2.0, an Introduction

WCAG (Web Content Accessibility Guidelines) is the W3C’s strategy towards making the web accessible for all and making it useful for the people with disability to the limits possible.

Accessibility of the website has been concern for many of since decades but everybody tried to build his own set of accessibility standards. For example, to some people, if their website is accessible (useable) in all website browsers over desktop and hand-held devices, it is accessible to the world. Some believe if website has HTML menus which doesn’t require any 3rd party plugin (like flash installed or JavaScript enabled), their website is accessible to the world. Another level of accessibility could be having a clean HTML and CSS (w3c compliant) then this is yet again another level of accessibility.

Accessibility to W3C, however has different meanings and has defined a measuring mechanism to know if a website is really accessible or not. These W3C standards were at first introduced in 1999 as WCAG-1.0 and later reviewed, improved and redefined in 2007 to be called as WCAG 2.0.

WCAG 1.0 Stated

  • 1. Provide equivalent alternatives to auditory and visual content.
  • 2. Don't rely on color alone.
  • 3. Use markup and style sheets and do so properly.
  • 4. Clarify natural language usage
  • 5. Create tables that transform gracefully.
  • 6. Ensure that pages featuring new technologies transform gracefully.
  • 7. Ensure user control of time-sensitive content changes.
  • 8. Ensure direct accessibility of embedded user interfaces.
  • 9. Design for device-independence.
  • 10. Use interim solutions.
  • 11. Use W3C technologies and guidelines.
  • 12. Provide context and orientation information.
  • 13. Provide clear navigation mechanisms.
  • 14. Ensure that documents are clear and simple.

After review and improvements, the WCAG was rather identified to be function of 4 basic guiding principles including

WCAG 2.0 is was not just an approach to redefine accessibility guidelines and introduce an assessment criteria for each aspect, it was rather an attempt to define basic principles which would further direct usability criteria. These basic principles states that websites need to be

  1. 1.Perceivable
  2. 2.Accessible
  3. 3.Understandable
  4. 4.Robust

All the guidelines described by WCAG 2.0 has essence of one or more of these principles in it. WCAG 2.0 guild lines include

WCAG 2.0 Guidelines 

1 Perceivable

  • 1.1 Provide text alternatives for any non-text content so that it can be changed into other forms people need, such as large print, braille, speech, symbols or simpler language.
  • 1.2 Provide alternatives for time-based media.
  • 1.3 Create content that can be presented in different ways (for example simpler layout) without losing information or structure.
  • 1.4 Make it easier for users to see and hear content including separating foreground from background.

2 Operable

  • 2.1 Make all functionality available from a keyboard.
  • 2.2 Provide users enough time to read and use content.
  • 2.3 Do not design content in a way that is known to cause seizures.
  • 2.4 Provide ways to help users navigate, find content, and determine where they are.

3 Understandable

  • 3.1 Make text content readable and understandable.
  • 3.2 Make Web pages appear and operate in predictable ways.
  • 3.3 Help users avoid and correct mistakes.

4 Robust

  • 4.1 Maximize compatibility with current and future user agents, including assistive technologies.

WCAG Accessibility Levels:

WCAG 2.0 has further grouped these accessibility guidelines into 3 levels of implementation. These levels are called

  • Level A
  • Level AA
  • Level AAA

These grouping levels indicate the urgency by which a accessibility principle is needed. Level A includes the most needed accessibility aspect which should be implemented at high priority. Level AA indicates important usability aspect but helpful only after Level A has been implemented. Level AAA includes set of guidelines which are good to have but their absence may not make a website in accessible.

Accessibility of Word Wide Web

Idea of usability is complex and multifaceted. Making websites CONTENT accessible alone wouldn’t make World Wide Web accessible to its users. TECHNOLOGIES (communication) and PLATFORMS (devices and software) also have a shared responsibility to make World Wide Web accessible in true sense.

With that aspect in view, W3C has addressed other contributors who have a role to play in making website completely accessible for all. These contributors include

  • Website content
  • Web browsers and media players
  • Assistive technology (like screen readers, alternative keyboards, switches, scanning software, etc.)
  • Users' knowledge (experiences, and adaptive strategies)
  • Developers (designers, coders, authors)
  • Authoring tools (software that creates Web sites)
  • Evaluation tools (Web accessibility evaluation tools, HTML validators, CSS validators, etc.)

With this multifaceted nature of World Wide Web and its accessibility, W3C has outlined several guide lines for them which I include

  • ATAG - Authoring Tool Accessibility Guidelines () addresses authoring tools
  • WCAT – (Web Content Accessibility Guidelines) addresses Web content, and is used by developers, authoring tools, and accessibility evaluation tools
  • UAAG - User Agent Accessibility Guidelines) addresses Web browsers and media players, including some aspects of assistive technologies
  • W3C technical specifications (HTML, XML, CSS, SVG, SMIL, etc.)

WAI guidelines are based on the fundamental technical specifications of the Web, and are developed in coordination with:

Accessibility Validation Resources:

Since WCAG 2.0 is based on principles and has well-defied evaluation criteria, accessibility aspects of webpage can be evaluated by using one of several online accessibility evaluation tools listed by W3C. These tools are though 3rd party software and offer varying levels of evaluation (A, AA or AAA), most of them are good to find common accessibility aspects and eliminate them. Among listed validation tools, I have found ACheckher to be one of the better ones.

Learn more about Web Accessibility

To begin your journey towards accessibility, I would recommend a free accessibility course offered by OCAD University.

Website Accessibility Checklist:

W3C provides an online Accessibility Checklist which can help you see which of the accessibility aspects have been addressed. Useability.com.au also provides download PDF and DOCX versions of accessibility checklist for your paper based analysis.

Reading List on Accessibility

Useful Web Resources