Definition
The practice of building web pages usable by everyone regardless of ability or assistive technology—covering vision, mobility, auditory, and cognitive needs through semantic HTML, ARIA, and standards like WCAG and Section 508.
Why It Matters
A website that ignores accessibility guidelines isn’t just “poorly designed”—it’s a digital wall that excludes millions of people. Accessibility is the price of entry for a truly universal web; without it, we are building a segregated digital society.
Core Concepts
- WCAG: Web Content Accessibility Guidelines—the international accessibility standard.
- Section 508: US federal accessibility requirements for government sites.
- WAI-ARIA: Roles (
navigation,alert), states (aria-selected), and properties for dynamic UIs.
<!-- Using ARIA to improve accessibility for dynamic components -->
<button aria-expanded="false" aria-controls="menu-list">
Open Menu
</button>
<ul id="menu-list" role="menu" hidden>
<li role="menuitem">Profile</li>
</ul>- Vision: Screen readers, Braille displays, magnifiers require semantic structure and alt text.
- Mobility: Keyboard navigation, voice control, switch devices need focusable interactive elements.
- Auditory: Captions and transcripts for audio/video via WebVTT
<track>elements.