Web accessibility refers to the inclusive practice of removing barriers that prevent access to websites by people with disabilities. When sites are correctly designed, developed and edited, all users have equal access to information and functionality. For example, when a site is coded with semantically meaningful HTML, with textual equivalents provided for images and with links named meaningfully, this helps blind users using text-to-speech software and/or text-to-Braille hardware. When text and images are large and/or enlargeable, it is easier for users with poor sight to read and understand the content. When links are underlined (or otherwise differentiated) as well as colored, this ensures that color blind users will be able to notice them. When clickable links and areas are large, this helps users who cannot control a mouse with precision. When pages are coded so that users can navigate by means of the keyboard alone, or a single switch access device alone, this helps users who cannot use a mouse or even a standard keyboard. When videos are closed captioned or a sign language version is available, deaf and hard-of-hearing users can understand the video. When flashing effects are avoided or made optional, users prone to seizures caused by these effects are not put at risk. And when content is written in plain language and illustrated with instructional diagrams and animations, users with dyslexia and learning difficulties are better able to understand the content. When sites are correctly built and maintained, all of these users can be accommodated without decreasing the usability of the site for non-disabled users.
The needs that Web accessibility aims to address include:
- Visual: Visual impairments including blindness, various common types of low vision and poor eyesight, various types of color blindness;
- Motor/Mobility: e.g. difficulty or inability to use the hands, including tremors, muscle slowness, loss of fine muscle control, etc., due to conditions such as Parkinson's Disease, muscular dystrophy, cerebral palsy, stroke;
- Auditory: Deafness or hearing impairments, including individuals who are hard of hearing;
- Seizures: Photoepileptic seizures caused by visual strobe or flashing effects.
- Cognitive/Intellectual: Developmental disabilities, learning disabilities (dyslexia, dyscalculia, etc.), and cognitive disabilities of various origins, affecting memory, attention, developmental "maturity," problem-solving and logic skills, etc.
- 1 Assistive technologies used for web browsing
- 2 Guidelines on accessible web design
- 3 Essential components of web accessibility
- 4 Guidelines for different components
- 5 Legally required web accessibility
- 6 Website accessibility audits
- 7 Remediating inaccessible websites
- 8 Accessible Web applications and WAI-ARIA
- 9 See also
- 10 References
- 11 Further reading
- 12 External links
Assistive technologies used for web browsing
Individuals living with a disability use assistive technologies such as the following to enable and assist web browsing:
- Screen reader software, which can read out, using synthesized speech, either selected elements of what is being displayed on the monitor (helpful for users with reading or learning difficulties), or which can read out everything that is happening on the computer (used by blind and vision impaired users).
- Braille terminals, consisting of a Refreshable Braille display which renders text as Braille characters (usually by means of raising pegs through holes in a flat surface) and either a mainstream keyboard or a Braille keyboard.
- Screen magnification software, which enlarges what is displayed on the computer monitor, making it easier to read for vision impaired users.
- Speech recognition software that can accept spoken commands to the computer, or turn dictation into grammatically correct text - useful for those who have difficulty using a mouse or a keyboard.
- Keyboard overlays, which can make typing easier and more accurate for those who have motor control difficulties.
- Access to subtitled or sign language videos on the Internet for all deaf people.
Guidelines on accessible web design
Web Content Accessibility Guidelines
In 1999 the Web Accessibility Initiative, a project by the World Wide Web Consortium (W3C), published the Web Content Accessibility Guidelines WCAG 1.0. In recent years, these have been widely accepted as the definitive guidelines on how to create accessible websites.
On 11 December 2008, the WAI released the WCAG 2.0 as a Recommendation. WCAG 2.0 aims to be up to date and more technology neutral.
Criticism of WAI guidelines
For a general criticism of the W3C process, read Putting the user at the heart of the W3C process. There was a formal objection to WCAG's original claim that WCAG 2.0 will address requirements for people with learning disabilities and cognitive limitations headed by Lisa Seeman and signed by 40 organisations and people. In articles such as "WCAG 2.0: The new W3C guidelines evaluated", "To Hell with WCAG 2.0" and "Testability Costs Too Much", the WAI has been criticised for allowing WCAG 1.0 to get increasingly out of step with today's technologies and techniques for creating and consuming web content, for the slow pace of development of WCAG 2.0, for making the new guidelines difficult to navigate and understand, and other argued failings.
Canada has the Common Look and Feel Standards requiring federal government internet websites to meet Web Content Accessibility Guidelines (WCAG) 1.0 Checkpoints Priorities 1 and 2 (Double A conformance level). The standards have existed since 2000 and were updated in 2007. As of 2008, federal government internet websites follow the WCAG 2.0 (Priority Level AA) standards along with Common Look and Feel (CLF 2.0).
As part of the Web Accessibility Initiatives in the Philippines, the government through the National Council for the Welfare of Disabled Persons (NCWDP) board approved the recommendation of forming an adhoc or core group of webmasters that will help in the implementation of the Biwako Millennium Framework set by the UNESCAP.
The Philippines was also the place where the Interregional Seminar and Regional Demonstration Workshop on Accessible Information and Communications Technologies (ICT) to Persons with Disabilities was held where eleven countries from Asia - Pacific were represented. The Manila Accessible Information and Communications Technologies Design Recommendations was drafted and adopted in 2003.
In Spain, UNE 139803 is the norm entrusted to regulate web accessibility. This standard is based on Web Content Accessibility Guidelines 1.0.
In Sweden, Verva, the Swedish Administrative Development Agency is responsible for a set of guidelines for Swedish public sector web sites. Through the guidelines, Web accessibility is presented as an integral part of the overall development process and not as a separate issue.
The Swedish guidelines contain criteria which cover the entire lifecycle of a website; from its conception to the publication of live web content. These criteria address several areas which should be considered, including:
- web standards
- privacy issues
- information architecture
- developing content for the web
- Content Management Systems (CMS) / authoring tools selection.
- development of web content for mobile devices.
An English translation was released in April 2008: Swedish National Guidelines for Public Sector Websites
The translation is based on the latest version of Guidelines which was released in 2006.
In December 2010, the BSI (British Standards Institute) released the standard BS 8878:2010 Web accessibility. Code of practice. This standard effectively supersedes PAS 78 (pub. 2006). PAS 78, produced by the The Disability Rights Commission and British Standards Institution, provided guidance to organisations in how to go about commissioning an accessible website from a design agency. It describes what is expected from websites to comply with the UK Disability Discrimination Act 1995 (DDA), making websites accessible to and usable by disabled people.
BS 8878:2010 Web accessibility - Code of Practice. The standard has been designed to introduce non-technical professionals to improved accessibility, usability and user experience for disabled and older people. It will be especially beneficial to anyone new to this subject as it gives guidance on process, rather than on technical and design issues. BS 8878 is consistent with the Equality Act 2010  and is referenced in the UK government’s e-Accessibility Action Plan as the basis of updated advice on developing accessible online services. It includes recommendations for:
- Involving disabled people in the development process and using automated tools to assist with accessibility testing
- The management of the guidance and process for upholding existing accessibility guidelines and specifications.
BS 8878 is intended for anyone responsible for the policies covering web product creation within their organization, and governance against those policies (e.g. Chief Executive Officers, Managing Directors, Headteachers, ICT managers). It would also assist:
- People responsible for promoting and supporting equality and inclusion initiatives within an organization (e.g. Human Resource (HR) managers or those responsible for Corporate Social Responsibility - CSR).
- Procurement managers (e.g. those responsible for procuring web products or the tools to create them such as content production systems or virtual learning environments).
- Web production teams (e.g. product owners, project managers, technical architects and web developers, designers, usability and accessibility engineers, test engineers).
- People with responsibility for creating or shaping online content (e.g. website editors, marketing managers, web content authors).
- People who create web production, testing or validation tools.
- People who write and deliver training courses in web production, design or coding.
Other audiences that might also be interested in this British Standard include:
- Assistive technology creators, vendors and trainers who need insights into how their technologies impact on the production of accessible web products.
- Those disabled and older people whose web accessibility needs the Standard aims to support and present.
Its lead-author, Jonathan Hassell, has created a summary of BS 8878 to help organisations better understand how the standard can help them embed accessibility and inclusive design in their business-as-usual processes.
Web Content Accessibility Guidelines in Japan were established in 2004 as JIS (Japanese Industrial Standards) X 8341-3. JIS X 8341-3 was revised in 2010 to adopt WCAG 2.0. The new version has the same four principles, 12 guidelines, and 61 success criteria as WCAG 2.0 has.
Essential components of web accessibility
The accessibility of websites relies on the cooperation of eight components:
- the website itself - natural information (text, images and sound) and the markup code that defines its structure and presentation
- user agents, such as web browsers and media players
- assistive technologies, such as screen readers and input devices used in place of the conventional keyboard and mouse
- users' knowledge and experience using the web
- authoring tools
- evaluation tools
- a defined web accessibility standard, or a policy for your organization (against which to evaluate the accessibility)
These components interact with each other to create an environment that is accessible to people with disabilities.
Web developers usually use authoring tools and evaluation tools to create Web content.
People ("users") use Web browsers, media players, assistive technologies or other "user agents" to get and interact with the content."
Guidelines for different components
Authoring Tool Accessibility Guidelines (ATAG)
- ATAG contains 28 checkpoints that provide guidance on:
- producing accessible output that meets standards and guidelines
- promoting the content author for accessibility-related information
- providing ways of checking and correcting inaccessible content
- integrating accessibility in the overall look and feel
- making the authoring tool itself accessible to people with disabilities
Web Content Accessibility Guidelines (WCAG)
- WCAG 1.0: 14 guidelines that are general principles of accessible design
- WCAG 2.0: 12 principal guidelines
User Agent Accessibility Guidelines (UAAG)
- UAAG contains a comprehensive set of checkpoints that cover:
- access to all content
- user control over how content is rendered
- user control over the user interface
- standard programming interfaces
Legally required web accessibility
A growing number of countries around the world have introduced legislation which either directly addresses the need for websites and other forms of communication to be accessible to people with disabilities, or which addresses the more general requirement for people with disabilities not to be discriminated against.
In 2000, an Australian blind man won a court case against the Sydney Organizing Committee of the Olympic Games (SOCOG). This was the first successful case under Disability Discrimination Act 1992 because SOCOG had failed to make their official website, Sydney Olympic Games, adequately accessible to blind users. The Human Rights and Equal Opportunity Commission (HREOC) also published World Wide Web Access: Disability Discrimination Act Advisory Notes. All Governments in Australia also have policies and guidelines that require accessible public websites; Vision Australia maintain a complete list of Australian web accessibility policies.
In Brazil, the federal government published a paper with guidelines for accessibility in 18 January 2005, for public reviewing. In 14 December of the same year, the second version was published, including suggestions made to the first version of the paper. In 7 May 2007, the accessibility guidelines of the paper became compulsory to all federal websites. The current version of the paper, which follows the WCAG 2.0 guidelines, is named e-MAG, Modelo de Acessibilidade de Governo Eletrônico (Electronic Government Accessibility Model), and is maintaned by Brazilian Ministry of Planning, Budget, and Management.
The paper can be viewed and downloaded at its official website.
In Ireland, the Disability Act 2005 requires that where a public body communicates in electronic form with one or more persons, the contents of the communication must be, as far as practicable, "accessible to persons with a visual impairment to whom adaptive technology is available" (Section 28(2)). The National Disability Authority has produced a Code of Practice giving guidance to public bodies on how to meet the obligations of the Act. This is an approved code of practice and its provisions have the force of legally binding statutory obligations. It states that a public body can achieve compliance with Section 28(2) by "reviewing existing practices for electronic communications in terms of accessibility against relevant guidelines and standards", giving the example of "Double A conformance with the Web Accessibility Initiative's (WAI) Web Content Accessibility Guidelines (WCAG)".
The Israeli Ministry of Justice recently published regulations requiring Internet websites to comply with Israeli standard 5568, which is based on the W3C Web Content Accessibility Guidelines 2.0. The main differences between the Israeli standard and the W3C standard concern the requirements to provide captions and texts for audio and video media. The Israeli standards are somewhat more lenient, reflecting the current technical difficulties in providing such captions and texts in Hebrew. 
In Italy, web accessibility is ruled by the so called "Legge Stanca" (Stanca Act), formally Act n.4 of 9 January 2004, officially published on the Gazzetta Ufficiale on 17 January 2004. The original Stanca Act was based on the WCAG 1.0. On 20 March 2013 the standards required by the Stanca Act were updated to the WCAG 2.0.
In the UK, the Equality Act 2010 does not refer explicitly to website accessibility, but makes it illegal to discriminate against people with disabilities. The Act applies to anyone providing a service; public, private and voluntary sectors. The Code of Practice: Rights of Access - Goods, Facilities, Services and Premises document published by the government's Equality and Human Rights Commission to accompany the Act does refer explicitly to websites as one of the "services to the public" which should be considered covered by the Act.
Website accessibility audits
A growing number of organizations, companies and consultants offer website accessibility audits. These audits, a type of system testing, identify accessibility problems that exist within a website, and provide advice and guidance on the steps that need to be taken to correct these problems.
A range of methods are used to audit websites for accessibility:
- Automated tools are available which can identify some of the problems that are present. Depending on the tool the result may vary widely making it difficult to compare test results.
- Expert technical reviewers, knowledgeable in web design technologies and accessibility, can review a representative selection of pages and provide detailed feedback and advice based on their findings.
- User testing, usually overseen by technical experts, involves setting tasks for ordinary users to carry out on the website, and reviewing the problems these users encounter as they try to carry out the tasks.
Each of these methods has its strengths and weaknesses:
- Automated tools can process many pages in a relatively short length of time, but can only identify some of the accessibility problems that might be present in the website.
- Technical expert review will identify many of the problems that exist, but the process is time consuming, and many websites are too large to make it possible for a person to review every page.
- User testing combines elements of usability and accessibility testing, and is valuable for identifying problems that might otherwise be overlooked, but needs to be used knowledgeably to avoid the risk of basing design decisions on one user's preferences.
Ideally, a combination of methods should be used to assess the accessibility of a website.
Remediating inaccessible websites
Once an accessibility audit has been conducted, and accessibility errors have been identified, the errors will need to be remediated in order to ensure the site is compliant with accessibility errors. The traditional way of correcting an inaccessible site is to go back into the source code, reprogram the error, and then test to make sure the bug was fixed. If the website is not scheduled to be revised in the near future, that error (and others) would remain on the site for a lengthy period of time, possibly violating accessibility guidelines. Because this is a complicated process, many website owners choose to build accessibility into a new site design or re-launch, as it can be more efficient to develop the site to comply with accessibility guidelines, rather than to remediate errors later. In addition to these methods, a new technology called Amaze uses a technique called accessibility overlays, which correct the error on the server-side, allowing the sites to be made accessible directly to the end user.
Accessible Web applications and WAI-ARIA
- Accessible publishing
- Augmentative and alternative communication
- Computer accessibility
- Digital divide
- Device Independence
- European Internet Accessibility Observatory
- Maguire v SOCOG 2000
- Multimodal interaction
- Progressive enhancement
- Universal design
- Web Interoperability
- Web Engineering
- "Accessibility SIG Meeting 24th July 2007 - CETISwiki". Wiki.cetis.ac.uk. Retrieved 2013-07-28.
- Lisa Seeman (20 June 2006). "Formal Objection to WCAG 2.0". W3C Public Mailing List Archives. Retrieved 2012-12-16.
- Trenton Moss says:. "WCAG 2.0: The new W3C accessibility guidelines evaluated". Webcredible.co.uk. Retrieved 2013-07-28.
- Joe Clark (2013-07-11). "To Hell with WCAG 2 · An A List Apart Article". Alistapart.com. Retrieved 2013-07-28.
- Gian Sampson-Wild (2013-07-11). "Testability Costs Too Much · An A List Apart Article". Alistapart.com. Retrieved 2013-07-28.
- "La norma UNE 139803:2004 constituye la base de la certificación en Accesibilidad Web." (in Spanish). INTECO. Retrieved 2012-12-16.
- [dead link]
- Peter Krantz (2006). "New Version of Guidelines for Swedish Public Sector Web Sites". www.standards-schmandards.com. Retrieved 2012-12-18.
- "Equality Act 2010". Legislation.gov.uk. Retrieved 2013-07-28.
- "BS 8878 web accessibility standards - all you need to know". Hassell Inclusion. Retrieved 2013-07-28.
- "JIS X 8341-3" (in Japanese). Wikipedia. Retrieved 2012-12-18.
- Shawn Lawton Henry (August 2005). "Essential Components of Web Accessibility". World Wide Web Consortium. Retrieved 2012-12-18.
- Shawn Lawton Henry (December 2008). "Authoring Tool Accessibility Guidelines (ATAG) Overview". World Wide Web Consortium. Retrieved 2012-12-18.
- Shawn Lawton Henry (July 2005). "User Agent Accessibility Guidelines (UAAG) Overview". World Wide Web Consortium. Retrieved 2012-12-18.
- "World Wide Web Access: Disability Discrimination Act Advisory Notes ver 4.0 (2010) | Australian Human Rights Commission". Hreoc.gov.au. 2010-07-01. Retrieved 2013-07-28.
- "e-MAG - Modelo de Acessibilidade de Governo Eletrônico". GovernoEletronico.gov.br. Retrieved 2014-01-04.
- "Disability Act 2005 - Tithe an Oireachtais". Oireachtas.ie. 2009-11-13. Retrieved 2013-07-28.
- "Code of Practice on Accessibility of Public Services and Information Provided by Public Bodies". Nda.ie. 2006-07-21. Retrieved 2013-07-28.
- "Israel Technology Law Blog, Website Accessibility Requirements".
- "A guide to good practice in commissioning accessible websites". Equality and Human Rights Commission. Retrieved 2012-12-18.
- Krantz, Peter. "Pitfalls of Web Accessibility Evaluation Tools". Standards-schmandards.com. Retrieved 23 December 2012.
- "Accessible Rich Internet Applications (WAI-ARIA) 1.0". World Wide Web Consortium. 12 December 2012. Retrieved 2012-12-18.
- Clark, Joe (2003). Building Accessible Websites. New Riders Press. ISBN 0-7357-1150-X.
- Thatcher, Jim; Cynthia Waddell, Shawn Henry, Sarah Swierenga, Mark Urban, Michael Burks, Paul Bohman (2003). Constructing Accessible Web Sites (Reprint ed.). Apress (Previously by Glasshaus). ISBN 1-59059-148-8.
- Slatin, John; Sharron Rush (2002). Maximum Accessibility: Making Your Web Site More Usable for Everyone. Addison-Wesley Professional. ISBN 0-201-77422-4.
- Paciello, Michael (2000). Web Accessibility for People with Disabilities. CMP Books. ISBN 1-929629-08-7.
- Bangeman, Eric (2006-09-10). "Judge: ADA lawsuit against Target can proceed". Ars Technica. Retrieved 2006-09-26.
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Standards and guidelines
- The main page for the W3C's Web Accessibility Initiative (WAI)
- Equality and Human Rights Commission: PAS 78: a guide to good practice in commissioning accessible websites (which BS 8878 supersedes)
- Unified Web Evaluation Methodology 1.2
- HTML Heading Semantics-Learn how HTML semantics are important to web accessibility.
- Good website reviewing the WCAG 2.0
- Good Article with much informative comments about Web Guidelines and WCAG 2.0
- University of Illinois iCITA HTML Accessibility Best Practices
- New York State Mandatory Technology Standards for Accessibility of State Agency Web-Based Intranet and Internet Information and Applications–Fourteen standards derived from both U.S. Section 508 and the WAI's WCAG 1.0 and required for NYS agency web sites.
- Guidelines for Complying with Section 508 of the Rehabilitation Act and Section 508 Homepage
- Microsoft accessibility portal
- E accessibility
- Searchable index of government web guidelines
- UK Equality Act 2010 which supersedes UK Disability Discrimination Act
- The Americans with Disabilities Act of 1990 (ADA) does not require websites to be accessible. However, since June 2010 the U.S. Department of Justice is considering to amend the ADA on this particular point.
- Section 508 of the Rehabilitation Act - requires U.S. government web sites to be accessible
- New York State Technology Policy P04-002–Requires Accessibility of State Agency Web-Based Intranet and Internet Information and Applications, requires all State entity web sites to be accessible according to NYS standards which are a hybrid of Section 508 and the W3C's WCAG 1.0. Updates Statewide Technology Policy 99-3, which required sites to conform to the W3C WCAG 1.0, Priority one checkpoints only.
- Disability Act 2005 Ireland
- Common Look and Feel Standards 2.0 Canada
- The Foundation for Information Technology Accessibility (Malta)