Important note: This Wiki page is edited by participants of the EOWG. It does not necessarily represent consensus and it may have incorrect information or information that is not supported by other Working Group participants, WAI, or W3C. It may also have some very useful information.

Basics with Notes

From Education & Outreach
Revision as of 11:49, 1 June 2012 by Shawn (Talk | contribs)

(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Jump to: navigation, search

Nav: EOWG wiki main page > Curriculum & Course Materials > Web Accessibility Basics

{@@editorial notes: See the Discussion tab for audience analysis, etc.}

{@@ markup comments and notes like this...}

{@@editorial note: We'd like to use wording from approved WAI publications where it works, rather than using lots of new wording on this page. (for consistency and to shortcut additional vetting needed)}

Web Accessibility Basics - Version with Notes

On this page:

This page provides an overview of web accessibility and links to resources for more information. We suggest that you read through this whole page first, then go back and follow the links to learn more.

The Web is for all people

The Web is fundamentally designed to work for all people, whatever their hardware, software, language, culture, location, or physical or mental ability. When the Web meets this goal, it is accessible to people with a diverse range of hearing, movement, sight, and cognitive ability.

Thus the impact of disability is radically changed on the Web because the Web removes barriers to communication and interaction that many people face in the physical world. However, when websites, web technologies, or web tools are badly designed, they can create barriers that exclude people from using the Web.

For an introduction to why - case for web accessibility, what - examples of web accessibility, and how to make your website and web tools accessible, see Accessibility - W3C.

What is web accessibility

Web accessibility means that people with disabilities can use the Web. More specifically, it means that people with disabilities can perceive, understand, navigate, and interact with the Web, and that they can contribute to the Web.

Web accessibility encompasses all disabilities that affect access to the Web, including people with auditory, cognitive, neurological, physical, speech, and visual disabilities.

While accessibility focuses on people with disabilities, it also benefits others. Accessibility supports social inclusion for people with disabilities, older people, and mobile users, as well as many others, including people with low literacy, people in rural areas, people who only have access to low bandwidth connections, etc. More information is in #Mobile users below, #Older people below, and Web Accessibility Benefits People With and Without Disabilities.

Understand how people use the Web

Stories about people using the Web help to illustrate the everyday needs of people with disabilities. For example:

  • Ms. Olsen attends middle school, and particularly likes her literature class. She has attention deficit hyperactivity disorder (ADHD) with dyslexia, and the combination leads to substantial difficulty reading.
  • Ms. Laitinen is the chief accountant at an insurance company that uses web-based documents and forms over a corporate intranet. She is blind and, like many other blind computer users, does not read braille.
  • Mr. Yunus is 85 years old and started to use the Web several years ago to stay in touch with family and friends, and to read about art history. He has reduced vision, hand tremor, and mild short-term memory loss.

To learn how these people and others use with the Web, see Stories of Web Users.

{@@review}It is important to consider the broad diversity of functional needs and how an individual may encounter barriers to accessing web content. For example: a person with a hearing impairment will not be able to hear the audio track on a video, or a person with a cognitive impairment may have difficulty understanding how to navigate a complex website or unusual page layout, or a person with physical impairment affecting his or her hand may be unable to navigate with a mouse.

The diversity of abilities include auditory, cognitive and neurological, physical, speech, and visual disabilities. To learn more about the diversity of abilities of Web users, see Diversity of Web Users.

People with disabilities access and navigate the Web in different ways, depending on their individual needs and preferences. Sometimes people configure standard software and hardware according to their needs, and sometimes people use specialized software or hardware that help them perform certain tasks. To learn about the techniques and tools that people with disabilities use to interact with the Web, such as browser settings, text-to-speech, voice recognition, see Diversity in Web Use.

Accessibility requirements

Accessibility requirements can be categorized under 4 basic principles:

  • Perceivable information and user interface - e.g., text alternative for images and captions for video; adaptable content; content that is easy to see and hear
  • Operable user interface and navigation - e.g., keyboard access; users can easily navigate, find content, and determine where they are
  • Understandable information and user interface - e.g., content works in predictable ways; users are helped to avoid and correct mistakes
  • Robust content and reliable interpretation - e.g., works with users' browsers and other tools

For a quick idea of 3 web accessibility issues (alternative text for images, keyboard input, and transcripts), see What: Examples of Web Accessibility.

See Accessibility Principles to learn about web accessibility requirements. With short paragraphs and lists, this page is easier to read than the formal standards/guidelines. It includes links to the standards so that you can get the definitive information when you want it.

{@@Suzette: this is the sort of sentence I was trying to avoid - it is descriptive but has no useful content (sorry!). The link points to some well written material on about 12 common accessibility issues. I would propose bringing a few sentences from there to here - readers can judge for themselves whether they might find it easier to read. I am happy to do that for next week if you set an Action on me}

The components of web accessibility

It is essential that several different components of Web development and interaction work together in order for the Web to be accessible to people with disabilities. WAI provides accessibility guidelines that cover these components.

Web Content

Content is the information in a web page or web application, including: natural information such as text, images, and sounds; code or markup that defines structure, presentation, interaction, etc. Content requirements are covered in Web Content Accessibility Guidelines (WCAG).

The WCAG documents explain how to make web content (including web applications) more accessible to people with disabilities. To learn more about WCAG, see:

Most people will use the supporting materials when developing Web content and Web tools, instead of the actual technical standards document. The WCAG supporting technical materials are introduced in The WCAG 2.0 Documents.

WCAG Techniques give specific guidance for developers on how to develop accessible web content. The techniques are "informative", that is, you do not have to use them. The basis for determining conformance to WCAG 2.0 is the success criteria from the WCAG 2.0 standard, not the techniques. To learn more about techniques, see About the Techniques.

{@@ Suzette: I note that 3 of these links point to the same place - we should just chose one. I am not sure that the text and links are clearly distinguishing between the Guidelines themselves, and the introductory materials and the more detailed expanatory techniques and understanding docs. I would suggest building up logically from easy to practical to formal the 'intro pages, then techniques and understanding docs, then the actual WCAG 2.0. Readers can then pick their preferred level to aim for. Again I am happy to edit for next week if you would like me to follow this up}


The tools that we use to create and use web content play an important role in accessibility.

  • Authoring tools are software that creates websites, including content management systems (CMS), HTML editors, websites that let users add content, and other tools. {@@review}These tools can help create accessible content, or can make it more difficult to create accessible content. Tools should support developers in making their web content accessible, and should be accessible themselves so that people with disabilities can use the tools. This is covered in Authoring Tool Accessibility Guidelines (ATAG).
  • Evaluation tools help check if websites meet standards. (Relevant information is in Selecting Web Accessibility Evaluation Tools.)
  • Web browsers, media players, and other "user agents" are covered in User Agent Accessibility Guidelines (UAAG).
  • Assistive technologies, such as screen readers, alternative keyboards, switches, scanning software, etc., are used by some people. (Introduced in Diversity in Web Use.)

{@@ Suzette: See first sentence of this section marked for review. I think as a general principle people use tools to perform tasks. I would therefore suggest "Authoring tools are software applications that are used to create and edit websites. For example...}


People need to understand and implement accessibility. This includes designers, coders, authors, managers, etc., anyone who is involved with developing content (including applications), authoring tools, evaluation tools, browsers and other user agents.

Users' knowledge, experiences, and skill using the Web — including for some users, assistive technologies or other adaptive strategies — also impact accessibility.

For more information on these components, see Essential Components of Web Accessibility and the "Components of Web Accessibility" Presentation.

Business case

The Web is increasingly an essential resource for many aspects of life: education, employment, government, commerce, health care, recreation, social interaction, and more. The Web is used not only for receiving information, but also for providing information and interacting with society. Therefore, it is essential that the Web be accessible in order to provide equal access and equal opportunity to people with disabilities. Indeed, the United Nations recognizes web accessibility as a basic human right.

In order for organizations to be willing to make the initial investment in accessibility, many need to understand the financial benefits of web accessibility. To learn more about the financial, technical, social, and legal and policy factors, see Developing a Web Accessibility Business Case for Your Organization and "Web Accessibility is Smart Business" Presentation.

Mobile users

With global mobile phone use at an all time high, there has been a surge of interest in developing websites that are accessible from a mobile device. Users of mobile devices and people with disabilities experience similar barriers when interacting with Web content. Websites can more efficiently meet both goals when developers understand the significant overlap between making a website accessible for a mobile device and for people with disabilities. For more information, see Web Content Accessibility and Mobile Web: Making a Web Site Accessible Both for People with Disabilities and for Mobile Devices.

Older users

Older Web users are an increasing market segment and an important target group for many businesses, governments, and other organizations. Many older people have age-related impairments that can affect how they use the Web, such as declining vision, physical ability, hearing, and cognitive ability. These issues overlap with the accessibility needs of people with disabilities. Thus, websites and tools that are accessible to people with disabilities are more accessible to older users as well. For more information, see Web Accessibility and Older People: Meeting the Needs of Ageing Web Users.

Learn more from W3C WAI

The W3C Web Accessibility Initiative (WAI) brings together people from industry, disability organizations, government, and research labs from around the world to develop guidelines and resources to help make the Web accessible to people with disabilities. We encourage you to look around the WAI website and find more information that is useful to you. See Finding Your WAI ("way") to New Web Accessibility Resources.

References and acknowledgements

Referencing this information: Most of the text on this page comes from other documents, which are linked within each section. For references, please use the source document. (See Using WAI Material: Permission to Use with Attribution.)

Editors: Shawn Lawton Henry, Shadi Abou-Zahra, Suzette Keith, Vicki Menezes Miller.

Contributors: Denis Boudreau, Sharron Rush, and other W3C WAI Education and Outreach Working Group (EOWG) participants.