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Chapter 1 of 8

Foundations of Web Accessibility

Web accessibility is the practice of building websites and applications that people with disabilities can perceive, understand, navigate, and use. It is not a niche concern but a quality discipline that improves inclusion, usability, legal compliance, and overall product quality for everyone. When teams treat accessibility as a cleanup task at the end of a project, they end up with fragile fixes that miss systemic issues; the most effective approach is to build accessibility checks into design, development, testing, and review from the very beginning.

The central international standard for evaluating digital accessibility is the Web Content Accessibility Guidelines, commonly known as WCAG, which is maintained by the W3C's Web Accessibility Initiative (WAI). WCAG is organized around four foundational principles, often remembered by the acronym POUR: content must be Perceivable, Operable, Understandable, and Robust. Each principle is supported by a set of testable success criteria grouped into three conformance levels. Level A is the minimum, Level AA is the target referenced by most regulations and represents practical, substantial coverage, and Level AAA is the highest standard that is often impractical to meet across an entire site.

Accessibility is not only an ethical and design issue but also a legal one in many jurisdictions. In the United States, the Americans with Disabilities Act (ADA) has been extended by courts to cover digital properties, and Section 508 requires federal agencies to make electronic content accessible, referencing WCAG 2.0 AA. In the European Union, the European Accessibility Act (EAA), which takes effect in 2025, requires digital products and services to meet accessibility standards. Because most major regulations point to WCAG AA, teams should treat that level as their baseline target and publish an accessibility statement that acknowledges the current status, known issues, and a contact path for users who encounter barriers.

All chapters
  1. 1Foundations of Web Accessibility
  2. 2The POUR Principles in Practice
  3. 3Semantic HTML and ARIA
  4. 4Keyboard Navigation and Focus Management
  5. 5Visual Accessibility
  6. 6Forms, Images, and Document Structure
  7. 7Dynamic Interfaces and Complex Components
  8. 8Testing, Cognitive Accessibility, and Inclusive Design

Drill it

Reading is not remembering. These come from the Web Accessibility deck:

Q

What is web accessibility?

Web accessibility is the practice of building websites and apps that people with disabilities can perceive, understand, navigate, and use.

Q

Why does accessibility matter?

It improves inclusion, usability, legal compliance, and overall product quality for everyone.

Q

What is WCAG?

WCAG stands for Web Content Accessibility Guidelines, the main standard used to evaluate digital accessibility.

Q

What are the four WCAG principles?

Content should be Perceivable, Operable, Understandable, and Robust.