Web Content Accessibility Guidelines
Web Content Accessibility Guidelines (WCAG) are part of a series of web accessibility guidelines published by the Web Accessibility Initiative (WAI) of the World Wide Web Consortium's (W3C), the main international standards organization for the World Wide Web. They consist of a set of guidelines for making content accessible, primarily for people with disabilities, but also for all user agents, including highly limited devices, such as mobile phones. The current version, WCAG 2.0, was published in December 2008 and is also an ISO standard, ISO/IEC 40500:2012.
The first web accessibility guideline was compiled by Gregg Vanderheiden and released in January 1995 just after the 1994 Second International Conference on the World-Wide Web (WWW II) in Chicago (where Tim Berners-Lee first mentioned disability access in a keynote speech after seeing a pre-conference workshop on accessibility led by Mike Paciello).
Over 38 different Web access guidelines followed from various authors and organizations over the next few years. These were brought together in the Unified Web Site Accessibility Guidelines compiled by the at the University of Wisconsin-Madison. Version 8 of the Unified Web Site Accessibility Guidelines, published in 1998, was used as the starting point for the W3C's WCAG 1.0.
The WCAG 1.0 was published and became a W3C recommendation on 5 May 1999. They have since been superseded by WCAG 2.0.
WCAG 1.0 consist of 14 guidelines which are general principles of accessible design. Each guideline covers a basic theme of web accessibility and is associated with one or more checkpoints describing how to apply that guideline to particular features of webpages.
- Guideline 1: Provide equivalent alternatives to auditory and visual content
- Guideline 2: Don’t rely on colour alone
- Guideline 3: Use markup and style sheets, and do so properly
- Guideline 4: Clarify natural language usage
- Guideline 5: Create tables that transform gracefully
- Guideline 6: Ensure that pages featuring new technologies transform gracefully
- Guideline 7: Ensure user control of time sensitive content changes
- Guideline 8: Ensure direct accessibility of embedded user interfaces
- Guideline 9: Design for device independence
- Guideline 10: User interim solutions
- Guideline 11: Use W3Ctechnologies and guidelines
- Guideline 12: Provide context and orientation information
- Guideline 13: Provide clear navigation mechanisms
- Guideline 14: Ensure that documents are clear and simple
Each of the in total 65 WCAG 1.0 checkpoints has a priority level assigned to it which is based on the checkpoint's impact on accessibility:
- Priority 1: Web developers must satisfy these requirements, otherwise it will be impossible for one or more groups to access the Web content. Conformance to this level is described as A.
- Priority 2: Web developers should satisfy these requirements, otherwise some groups will find it difficult to access the Web content. Conformance to this level is described as AA or Double-A.
- Priority 3: Web developers may satisfy these requirements, in order to make it easier for some groups to access the Web content. Conformance to this level is described as AAA or Triple-A.
WCAG 2.0 was published as a W3C Recommendation on 11 December 2008. It consists of 12 guidelines organized under 4 principles (perceivable, operable, understandable, and robust) and each guideline has testable success criteria.
Perceivable – Information and user interface components must be presentable to users in ways they can perceive.
- Guideline 1.1: Information and user interface components must be presentable to users in ways they can perceive.
- Guideline 1.2: Time-based Media: Provide alternatives for time-based media.
- Guideline 1.3: Create content that can be presented in different ways (for example simpler layout) without losing information or structure.
- Guideline 1.4: Make it easier for users to see and hear content including separating foreground from background.
Operable – User interface components and navigation must be operable.
- Guideline 2.1: Make all functionality available from a keyboard.
- Guideline 2.2: Provide users enough time to read and use content.
- Guideline 2.3: Do not design content in a way that is known to cause seizures.
- Guideline 2.4: Provide ways to help users navigate, find content, and determine where they are.
Understandable – Information and the operation of user interface must be understandable.
- Guideline 3.1: Make text content readable and understandable.
- Guideline 3.2: Make Web pages appear and operate in predictable ways.
- Guideline 3.3: Help users avoid and correct mistakes.
Robust – Content must be robust enough that it can be interpreted reliably by a wide variety of user agents, including assistive technologies.
- Guideline 4.1.: Maximize compatibility with current and future user agents, including assistive technologies.
WCAG 2.0 uses the same three levels of conformance (A, AA, AAA) as WCAG 1.0, but has redefined them. The WCAG working group maintains an extensive list of web accessibility techniques and common failure cases for WCAG 2.0.
- Document history
The first concept proposal of WCAG 2.0 was published on 25 January 2001. In the following years new versions were published intended to solicit feedback from accessibility experts and members of the disability community. On 27 April 2006 a "Last Call Working Draft" was published. Due to the many amendments that were necessary, WCAG 2.0 was published again as a concept proposal on 17 May 2007, followed by a second "Last Call Working Draft" on 11 December 2007. In April 2008 the guidelines became a "Candidate Recommendation". On 3 November 2008 the guidelines became a "Proposed Recommendation". WCAG 2.0 as published as a W3C Recommendation on 11 December 2008.
The Web Accessibility Initiative is working on guidance for migrating from WCAG 1.0 to WCAG 2.0. A comparison of WCAG 1.0 checkpoints and WCAG 2.0 success criteria is available.
Businesses that have an online presence should provide accessibility to disabled users. Not only are there ethical and commercial justifications for implementing the Web Content Accessibility Guidelines, there are also legal reasons. If a business's website does not meet the Accessibility Guidelines, then the website owner could be sued for discrimination.
On 27 January 2012, the Royal National Institute for the Blind (RNIB) in the United Kingdom issued a press release stating that it had served legal proceedings against low-cost airline bmibaby over their "failure to ensure web access for blind and partially sighted customers". To date, at least two actions against websites have been initiated by the RNIB, and both settled without the case being heard by a court.
Additionally, there has been one case of electronic accessibility that resulted in an employment tribunal finding discrimination. The case, against the Project Management Institute (PMI), was decided in October 2006, and the company was ordered to pay compensation of £3,000.
The landmark 2010/2012 Jodhan decision has caused the Canadian Federal government to require all online web pages, documents and videos available externally and internally to meet the accessibility requirements of WCAG 2.0.
It is anticipated that higher-profile test cases will be launched against non-compliant websites in the near future. Since the law requires websites to take "reasonable steps" to make websites accessible to users, it is anticipated that large companies will struggle to justify any failures to make their websites accessible, while small businesses and charities may have a better defense, if they can show that they do not have the resources necessary for the development work.
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. 
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- Web Content Accessibility Guidelines (WCAG) 1.0
- Web Content Accessibility Guidelines (WCAG) 2.0
- WAI Introduction to WCAG
- WCAG 2.0 Tutorial
- WAVE – Online Accessibility validator
- WCAG 2.0 checklist
- Achieving WCAG 2.0 with PDF/UA – Document published by the Association for Information and Image Management (AIIM)