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Web Accessibility Basics

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

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{@@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)}

{@@ to be written: brief introductory paragraph saying this page gives overview of key topics and links to resources for more info. Maybe suggest reading through the whole page first, then going back and following links. }

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.

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

Accessibility is about people with disabilities using the web

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, as introduced below.

Understand how people use the Web

Using the Web has become an essential part of everyday life including at work, school and leisure. People with disabilities use the Web for the same reasons as everyone else. Sometimes it may have additional benefits because the content can be presented in a more accessible format.

{@@ to be written: intro sentence for this section. Suzette_opening sentence to focus on people and goals}

People with disabilities

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

  • Ms. Kaseem, is teenager with deaf-blindness. Ms. Kaseem uses the Web to find new restaurants to go to with friends and classmates. She is deaf and recently became legally blind too, but she can see small portions of a screen.
  • 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.
  • 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.To use her computer and the Web, Ms. Laitinen uses:
    • Screen reader software that interprets what is displayed on the screen and generates speech output.
    • Web browser with keyboard support to help use websites without a mouse.


  • {@@ ACTION, Suzette: update examples per 13 April EOWG discussion. Suzette_I've added 3 to give a variety of age, needs and impairments }
  • ...

For more stories about how people with disabilities use the web, see Stories of Web Users.


Understanding disabilities

There are many reasons why people may be experiencing varying degrees of auditory, cognitive, neurological, physical, speech, and visual disabilities. For instance, some may have disabilities from birth, an illness, disease, or accident, or they may develop impairments with age. Some may not consider themselves to have disabilities even if they do experience such functional limitations.

Disability is complex - some people may have mild to moderate difficulties perceiving or operating a computer. For example there is a considerable functional difference between having low vision and being blind, or between having weakness in the fingers and paralysis or a missing limb. Real people may be affected by more than one impairment or their symptoms may vary over time.

  • For more information about disabilities, including auditory and visual, speech, physical and cognitive and neurological see Diversity of Web Users

Understanding assistive technologies, tools and strategies

People with disabilities access and navigate the Web in different ways, depending on their individual needs and preferences. Sometimes people use specialized software or hardware that help them perform certain tasks. These are known as assistive technologies, for example people who are blind may use screen readers to read the web page aloud, or people with difficulty using a keyboard may use a voice recognition system that can convert speech into written text.

Sometimes people configure standard software and hardware according to their needs, such as enlarge text fonts, changing colours or reducing mouse speed.

  • For more information about the technologies, tools and strategies used to interact with webpages see Diversity in Web Use


{Suzette - given the confusion between diversity'in use' and 'of users' I have restructure this section as two separate paragraphs}

Older users, mobile users, and more

Accessibility supports social inclusion for people with disabilities, older people, mobile users and others, such as people with low literacy, people in rural areas, people who only have access to low bandwidth connections, etc. For more information, see Web Accessibility Benefits People With and Without Disabilities

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

Mobile users... {@@to be written: taster on mobile, maybe edit of: 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. See: Web Content Accessibility and Mobile Web: Making a Web Site Accessible Both for People with Disabilities and for Mobile Devices

{@@comment Vicki: first paragraph, removed the link on "others" and added the full title of the link. Under "Mobile users", minor edits done, replaced second sentence @@question Vicki: should this group "Older users, mobile users, and more" be shifted to the information under the heading "The Web is for All People"}

Accessibility principles

Accessibility requirements can be categorized under 4 basic principles:

  • Perceivable information and user interface - e.g., text alternative for images, multimedia, and other non-text content; 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 'user agents'

{@@ review note- above is a draft - we should think about what to put as examples if we leave it like this ~shawn}

What: Examples of Web Accessibility introduces alternative text for images, keyboard input, and transcripts.

To learn more about web accessibility requirements for websites, web applications, browsers, and other tools, see Accessibility Principles.

The big picture (essential components)

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. These components include:

  • Content - the information in a web page or web application.
  • Tools:
    • Web browsers, media players, and other "user agents".
    • Assistive technology, in some cases - screen readers, alternative keyboards, switches, scanning software, etc.
    • Authoring tools - software that creates Web sites.
    • Evaluation tools that help check if websites meet standards
  • People:
    • Content developers - designers, coders, authors, etc., including developers with disabilities and users who contribute content.
    • Users' knowledge, experiences, and in some cases, adaptive strategies using the Web.
    • Tool developers -
    • {maybe include: people who develop payment systems, ticketing and booking systems, search tools, login tools and other apps. Is CMS and template creators here or part of authoring tools? Suzette}
    • {@@ question: list others, e.g., Manager... ?}

"There's an app for that" -- Well, there are web accessibility guidelines for the different technical components:

  • WCAG - Web Content Accessibility Guidelines - addresses web content (including applications), and is used by developers, authoring tools, and accessibility evaluation tools
  • ATAG - Authoring Tool Accessibility Guidelines - addresses authoring tools (content management systems, HTML editors, websites that let users add content, and more tools).
  • UAAG - User Agent Accessibility Guidelines - addresses web browsers and media players, including some aspects of assistive technologies

See Essential Components of Web Accessibility and the "Components of Web Accessibility" Presentation.

WCAG overview

The Web Content Accessibility Guidelines (WCAG) documents explain how to make web content more accessible to people with disabilities. Web "content" generally refers to the information in a Web page or Web application, including text, images, forms, sounds, and such.

To learn more about WCAG, see:

WCAG Documents and Techniques

"Most people will use the supporting materials when developing Web content and Web tools, instead of the actual technical standards document. The WCAG 2.0 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. About the Techniques explains this more. {@@editorial note: this will probably move to WCAg 2 FAQ soon}

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 UN Convention on the Rights of Persons with Disabilities (2006) recognizes Web accessibility as a basic human right."

Learn more about the social, technical, financial, and legal and policy factors in Developing a Web Accessibility Business Case for Your Organization. See also, "Web Accessibility is Smart Business" Presentation.


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.)

Contributors to this page: Suzette Keith, Shawn Lawton Henry, Shadi Abou-Zahra, Denis Boudreau, Vicki Menezes Miller, ..., and other W3C WAI Education and Outreach Working Group (EOWG) participants.




{@@[another version for consideration] Essential components - "the big picture"}

{shawn - maybe this gives too much focus on the guidelines for this page?}

"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. These components include:

  • Web Content (accessibility guidelines) - the information in a Web page or Web application.
    • Developers - including developers with disabilities and users who contribute content.
    • Conceptors{new term} - including analysts, information architects, usability specialists, designers, content writers, etc.
  • User agents (accessibility guidelines) - the various tools being used to access the Web page or Web application.
    • Web browsers - including {strike-through specific product list}Mozilla Firefox, Google Chrome, Microsoft Internet Explorer, Apple Safari, etc.
    • Assistive technology - including screen readers, alternative keyboards, switches, scanning software, etc.
    • Media players - including audio players, video players, etc.
  • Authoring tools (accessibility guidelines) - the software that creates Web sites or Web applications.
    • Editing tools - including HTML editing tools, WYSIWYG editing tools, text editing tools, etc.
    • Evaluation tools - including Web accessibility evaluation tools, HTML validators, CSS validators, etc.{shawn - ATAG for validators?}

{we should use existing wording when it works, e.g., http://www.w3.org/WAI/intro/people-use-web/principles#standards }

See Essential Components of Web Accessibility and the "Components of Web Accessibility" Presentation.