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Understanding Web Accessibility


This course focuses on developing an understanding of the World Wide Web Consortium's (W3C) Web Content Accessibility Guidelines Version 2.0 (WCAG 2.0). WCAG 2.0 describes how to make Web sites that are accessible to everyone.

What is this course about?

There are three audiences for this course:

  • Web developers
  • People who develop and implement accessibility policy
  • Decision-makers who need to know what their developers should be doing

What will you learn?

You will learn how Web sites are made accessible, and at the same time become familiar with WCAG 2.0. The organization of this course mirrors the structure of WCAG 2.0. Like it, the course is divided into four parts, or units. Each unit focuses on a principle of accessible Web content, with reasoning behind the principle, a translation of the associated guidelines, a simulation to experience barriers first hand, and then practice with strategies that can be used right away.
WCAG 2.0 categorized guidelines in three levels that represent the importance of each guideline. These levels are described as:

  • Level A: Must be done or some group will not be able to access the content.
  • Level AA: Should be done, or some group will have difficulty accessing the content.
  • Level AAA: Can be done to improve usability or enhance accessibility further.

What will you not learn?

This course does not cover every potential accessibility barrier, but rather focuses on the more common problems. Attending to the common barriers will address a large majority of accessibility issues in Web content. For more detailed coverage, follow the Additional Resources links included with each unit. This course does not address accessibility of non-W3C technologies, such as Microsoft Word documents, PDF files, or Flash. For information on making these forms of content accessible, refer to the documentation provided by their respective creators.

Course and Unit Structure

The four units of the course correspond to the four accessibility principles in the Web Content Accessibility Guidelines (WCAG). These principles describe Web content as:

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

Within each unit the learning materials are presented as follows:

  1. The Principle (A brief description of the principle)
  2. Reasons for Accessibility (A discussion of why the principle is important.)
  3. The Guidelines (A list of guidelines associated with the principle, along with "translations" into plain language.)/li>
  4. Experiencing Barriers (A simulation of barriers as they might be experienced by people with disabilities.)
  5. Ways to Avoid Creating Barriers (An introduction to accessible content authoring strategies)
    1. Success Criteria (Ways to conform with WCAG guidelines.)
    2. Sufficient Techniques (Strategies for creating accessible Web content.)
  6. Other Considerations (A discussion of accessibility issues not directly addressed by the guidelines.)
  7. Unit Exercise (Building practical experience.)
  8. Unit Quiz (Test your knowledge of the materials in the unit.)

How to Take the Course

Self-Guided Course

This is a self-guided course. Participants should begin by reading through the pages in the Course Introduction for an overview, then proceed in order through the four units that follow. There are no specific meeting times. You can take the course at times that are convenient for you. Begin each unit by reading the background information in the initial sections of the unit, trying the accessibility simulations to understand how barriers are experienced by people with disabilities, then trying some of the "Ways to Avoid Creating Barriers" to pick up techniques that can be used in your Web content. When you are confident you understand the content, complete the unit exercise and take the Unit Quiz to see how well you've learned the materials.

WCAG Principles Video

The following video by David MacDonald gives you a lighter look at the WCAG 2.0 principles. This is a music video of the WCAG 2.0 Theme Song, with people who have disabilities explaining the four WCAG 2.0 Principles. The four principles are also outlined in the Course Introduction. Click on the video to start it. (Requires Adobe Flash Player)

Note that YouTube videos, while now accessible to people who are deaf with the addition of captions, will not be accessible to some screen reader users. While it is possible to navigate through a YouTube video by keyboard, because readable text has not been included with the video controls, it is not possible to operate the video using a keyboard without being able to see where the cursor's focus lies. If you are using a screen reader, when you use the Tab key to navigate, you will hear nothing when you enter the video. Press the Enter key when this occurs, to start the video.

Resources and References

Become familiar with all the tools and resources listed below. They will prove invaluable when learning about accessibility, and as references once you have finished the course and are creating your own accessible content.

WCAG 2.0 References

Accessibility Evaluation Tools

Colour Analysis Tools

Captioning Tools

Screen Readers

Other Tools

About the Authors

Greg Gay

Greg Gay has been with the Inclusive Design Institute (formerly the Adaptive Technology Resource Centre) since 1996, and has played a variety of roles in managing accessibility related projects. He leads the ATutor project, which has developed an open source Learning Management System, the first to conform with international accessibility standards. He also leads the AChecker project, which has created an open source Web accessibility evaluation tool that allows Web developers and Web content authors to assess the accessibility of the information they post to the Web. Greg also runs the IDI Websavvy services, which provide accessibility evaluation and design services, as well as being involved in a variety of activities associated with the development of the W3C Web Content Accessibility Guidelines.

Alan Cantor

Alan Cantor does accessibility and usability testing, job accommodation, macro scripting, assistive technology training, and corporate training. His clients include Hewlett-Packard, Rogers Communications, CBC, the Government of Canada, the Accessibility Directorate of Ontario, and many banks, insurance companies, universities, school boards, health care facilities, and media organizations. Alan has been working to improve Web accessibility since 1996. He served for many years with the W3C WAI Education and Outreach Working Group, and is currently an invited expert for the W3C User Agent Accessibility Guidelines Working Group. Over the years, he has published many articles and guidelines about accessible information.