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WCAG Guidelines

WCAG Level AAA Requirements

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WCAG Level AAA: Enhanced Accessibility

Level AAA represents the highest level of accessibility conformance. While not required by most regulations, these 28 additional criteria provide enhanced accessibility for users with significant disabilities.

Important Considerations

Before pursuing Level AAA, understand that:

  1. Not Always Achievable: Some criteria cannot be met for all content types
  2. Not Legally Required: Most laws only require Level AA
  3. Selective Implementation: Organizations often implement specific AAA criteria that benefit their users
  4. Resource Intensive: Full AAA conformance requires significant effort

When to Pursue Level AAA

Consider Level AAA criteria when:

  • Your audience has high accessibility needs
  • You're in healthcare, education, or government
  • You want to be an accessibility leader
  • Specific criteria would greatly benefit your users

Perceivable (Level AAA)

1.2.6 Sign Language (Prerecorded)

Sign language interpretation is provided for all prerecorded audio content.

1.2.7 Extended Audio Description

Where pauses in audio are insufficient for audio descriptions, extended audio description is provided.

1.2.8 Media Alternative (Prerecorded)

A full text alternative is provided for all prerecorded synchronized media.

1.2.9 Audio-only (Live)

An alternative for time-based media is provided for live audio-only content.

1.4.6 Contrast (Enhanced)

Text must have a contrast ratio of at least:

  • 7:1 for normal text
  • 4.5:1 for large text
css
/* Enhanced contrast example */
.text {
  color: #000000;      /* Pure black */
  background: #ffffff; /* Pure white */
}
/* Ratio: 21:1 ✓✓✓ */

1.4.7 Low or No Background Audio

For prerecorded audio-only content containing primarily speech:

  • No background sounds, OR
  • Background sounds can be turned off, OR
  • Background sounds are at least 20 dB lower than speech

1.4.8 Visual Presentation

For blocks of text:

  • Foreground and background colors can be selected by the user
  • Width is no more than 80 characters
  • Text is not justified
  • Line spacing is at least 1.5 within paragraphs
  • Paragraph spacing is at least 1.5x line spacing
  • Text can be resized up to 200% without assistive technology
css
.article-content {
  max-width: 80ch;
  line-height: 1.6;
  text-align: left; /* Not justified */
}

.article-content p {
  margin-bottom: 1.5em;
}

1.4.9 Images of Text (No Exception)

Images of text are only used for pure decoration or where presentation is essential.

Operable (Level AAA)

2.1.3 Keyboard (No Exception)

All functionality must be operable through a keyboard with no exceptions.

This goes beyond 2.1.1 by eliminating the exception for functions that require analog input.

2.2.3 No Timing

Timing is not an essential part of the activity (except for real-time events and synchronized media).

2.2.4 Interruptions

Interruptions can be postponed or suppressed by the user.

2.2.5 Re-authenticating

When an authenticated session expires, the user can continue without loss of data after re-authenticating.

2.2.6 Timeouts

Users are warned of the duration of any user inactivity that could cause data loss.

2.3.2 Three Flashes

Web pages do not contain anything that flashes more than three times in any one second period.

2.3.3 Animation from Interactions

Motion animation triggered by interaction can be disabled.

css
/* Respect user preference for reduced motion */
@media (prefers-reduced-motion: reduce) {
  * {
    animation: none !important;
    transition: none !important;
  }
}

2.4.8 Location

Information about the user's location within a set of web pages is available.

html
<!-- Breadcrumb navigation -->
<nav aria-label="Breadcrumb">
  <ol>
    <li><a href="/">Home</a></li>
    <li><a href="/products">Products</a></li>
    <li aria-current="page">Widget Pro</li>
  </ol>
</nav>

2.4.9 Link Purpose (Link Only)

The purpose of each link can be identified from link text alone.

html
<!-- Level AA allows context -->
<p>Learn about <a href="/wcag">WCAG</a> guidelines.</p>

<!-- Level AAA requires self-explanatory links -->
<p><a href="/wcag">Learn about WCAG guidelines</a></p>

2.4.10 Section Headings

Section headings are used to organize content.

2.5.5 Target Size

The target size for pointer inputs is at least 44 by 44 CSS pixels.

css
button, a {
  min-width: 44px;
  min-height: 44px;
}

2.5.6 Concurrent Input Mechanisms

Content does not restrict use of input modalities available on a platform.

Understandable (Level AAA)

3.1.3 Unusual Words

A mechanism is available for identifying definitions of unusual words or phrases.

3.1.4 Abbreviations

A mechanism for identifying expanded forms of abbreviations is available.

html
<p>The <abbr title="Web Content Accessibility Guidelines">WCAG</abbr> 
provides accessibility standards.</p>

3.1.5 Reading Level

When text requires more advanced reading ability than lower secondary education level, supplemental content or an alternative version is available.

3.1.6 Pronunciation

A mechanism is available for identifying pronunciation of words.

3.2.5 Change on Request

Changes of context are initiated only by user request or a mechanism is available to turn off such changes.

3.3.5 Help

Context-sensitive help is available.

3.3.6 Error Prevention (All)

For all pages that accept user input:

  • Submissions are reversible, OR
  • Data is checked for errors, OR
  • A confirmation mechanism is provided

Practical AAA Implementation

Focus on these high-impact AAA criteria first:

  1. 1.4.6 Enhanced Contrast: Improves readability for everyone
  2. 2.3.3 Animation Control: Respects prefers-reduced-motion
  3. 2.4.10 Section Headings: Improves navigation and SEO
  4. 3.1.4 Abbreviations: Helps clarity
  5. 2.5.5 Target Size: Improves mobile usability

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