W3C Accessibility Standards Overview
The World Wide Web Consortium (W3C) develops international Web standards: HTML, CSS, and many more. W3C’s Web standards are called W3C Recommendations.
All W3C standards are reviewed for accessibility support by the Accessible Platform Architectures (APA) Working Group.
The standards and Notes (which are not standards) introduced below are particularly relevant to accessibility.
Web Content Accessibility Guidelines (WCAG)
Web “content” generally refers to 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, etc.
WCAG applies to dynamic content, multimedia, “mobile”, etc. WCAG can also be applied to non-web information and communications technologies (ICT), as described in WCAG2ICT.
Authoring Tool Accessibility Guidelines (ATAG)
Authoring tools are software and services that “authors” (web developers, designers, writers, etc.) use to produce web content. For example: HTML editors, content management systems (CMS), and websites that let users add content, such as blogs and social networking sites. ATAG documents explain how to: • make the authoring tools themselves accessible, so that people with disabilities can create web content, and • help authors create more accessible web content.
User Agent Accessibility Guidelines (UAAG)
User agents include browsers, browser extensions, media players, readers, and other applications that render web content.
Accessible Rich Internet Applications (WAI-ARIA)
ARIA provides semantics so authors can convey user interface behaviors and structural information to assistive technologies (such as screen readers). The ARIA specification provides an ontology of roles, states, and properties that define accessible user interface elements.
The ARIA suite includes API mapping specifications that provide user agent implementation guidance. It also include modules for Graphics and Digital Publishing.
- WAI-ARIA Overview – includes a list and description of modules and API mappings
- WAI-ARIA Authoring Practices
- WAI-ARIA 1.1 Standard
For Audio and Video
WebVTT: The Web Video Text Tracks Format is a format for captions, text video descriptions, and other metadata that is time-aligned with audio or video content.
Timed Text Markup Language is intended to be used for transcoding or exchanging timed text information among legacy distribution content formats for subtitling and captioning.
The following resources support development of accessibility evaluation methods and tools:
Accessibility Conformance Testing (ACT) Overview — ACT establishes and documents rules for testing the conformance of web content to accessibility standards.
Evaluation and Report Language (EARL) Overview — EARL is a machine-readable format for expressing test results.
Essential Components of Web Accessibility shows how Web accessibility depends on several components of web development and interaction working together, and how the WAI guidelines (WCAG, ATAG, UAAG) apply.
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