wcag-audit-patterns

wcag-audit-patterns

WCAG Audit Patterns

Comprehensive guide to auditing web content against WCAG 2.2 guidelines with actionable remediation strategies.

When to Use This Skill

• Conducting accessibility audits

• Fixing WCAG violations

• Implementing accessible components

• Preparing for accessibility lawsuits

• Meeting ADA/Section 508 requirements

• Achieving VPAT compliance

Core Concepts

1. WCAG Conformance Levels

Level Description Required For

A Minimum accessibility Legal baseline

AA Standard conformance Most regulations

AAA Enhanced accessibility Specialized needs

2. POUR Principles

Perceivable:  Can users perceive the content?
Operable:     Can users operate the interface?
Understandable: Can users understand the content?
Robust:       Does it work with assistive tech?

3. Common Violations by Impact

Critical (Blockers):
├── Missing alt text for functional images
├── No keyboard access to interactive elements
├── Missing form labels
└── Auto-playing media without controls

Serious:
├── Insufficient color contrast
├── Missing skip links
├── Inaccessible custom widgets
└── Missing page titles

Moderate:
├── Missing language attribute
├── Unclear link text
├── Missing landmarks
└── Improper heading hierarchy

Audit Checklist

Perceivable (Principle 1)

## 1.1 Text Alternatives

### 1.1.1 Non-text Content (Level A)

- [ ] All images have alt text
- [ ] Decorative images have alt=""
- [ ] Complex images have long descriptions
- [ ] Icons with meaning have accessible names
- [ ] CAPTCHAs have alternatives

Check:

```html
<!-- Good -->
<img src="chart.png" alt="Sales increased 25% from Q1 to Q2" />
<img src="decorative-line.png" alt="" />

<!-- Bad -->
<img src="chart.png" />
<img src="decorative-line.png" alt="decorative line" />

## 1.2 Time-based Media

### 1.2.1 Audio-only and Video-only (Level A)

-  Audio has text transcript

-  Video has audio description or transcript

### 1.2.2 Captions (Level A)

-  All video has synchronized captions

-  Captions are accurate and complete

-  Speaker identification included

### 1.2.3 Audio Description (Level A)

-  Video has audio description for visual content

## 1.3 Adaptable

### 1.3.1 Info and Relationships (Level A)

-  Headings use proper tags (h1-h6)

-  Lists use ul/ol/dl

-  Tables have headers

-  Form inputs have labels

-  ARIA landmarks present

Check:

### 1.3.2 Meaningful Sequence (Level A)

-  Reading order is logical

-  CSS positioning doesn't break order

-  Focus order matches visual order

### 1.3.3 Sensory Characteristics (Level A)

-  Instructions don't rely on shape/color alone

-  "Click the red button" → "Click Submit (red button)"

## 1.4 Distinguishable

### 1.4.1 Use of Color (Level A)

-  Color is not only means of conveying info

-  Links distinguishable without color

-  Error states not color-only

### 1.4.3 Contrast (Minimum) (Level AA)

-  Text: 4.5:1 contrast ratio

-  Large text (18pt+): 3:1 ratio

-  UI components: 3:1 ratio

Tools: WebAIM Contrast Checker, axe DevTools

### 1.4.4 Resize Text (Level AA)

-  Text resizes to 200% without loss

-  No horizontal scrolling at 320px

-  Content reflows properly

### 1.4.10 Reflow (Level AA)

-  Content reflows at 400% zoom

-  No two-dimensional scrolling

-  All content accessible at 320px width

### 1.4.11 Non-text Contrast (Level AA)

-  UI components have 3:1 contrast

-  Focus indicators visible

-  Graphical objects distinguishable

### 1.4.12 Text Spacing (Level AA)

-  No content loss with increased spacing

-  Line height 1.5x font size

-  Paragraph spacing 2x font size

-  Letter spacing 0.12x font size

-  Word spacing 0.16x font size

Operable (Principle 2)

## 2.1 Keyboard Accessible

### 2.1.1 Keyboard (Level A)
- [ ] All functionality keyboard accessible
- [ ] No keyboard traps
- [ ] Tab order is logical
- [ ] Custom widgets are keyboard operable

Check:
```javascript
// Custom button must be keyboard accessible
<div role="button" tabindex="0"
     onkeydown="if(event.key === 'Enter' || event.key === ' ') activate()">

2.1.2 No Keyboard Trap (Level A)

• Focus can move away from all components

• Modal dialogs trap focus correctly

• Focus returns after modal closes

2.2 Enough Time

2.2.1 Timing Adjustable (Level A)

• Session timeouts can be extended

• User warned before timeout

• Option to disable auto-refresh

2.2.2 Pause, Stop, Hide (Level A)

• Moving content can be paused

• Auto-updating content can be paused

• Animations respect prefers-reduced-motion

@media (prefers-reduced-motion: reduce) {
  * {
    animation: none !important;
    transition: none !important;
  }
}

2.3 Seizures and Physical Reactions

2.3.1 Three Flashes (Level A)

• No content flashes more than 3 times/second

• Flashing area is small (<25% viewport)

2.4 Navigable

2.4.1 Bypass Blocks (Level A)

• Skip to main content link present

• Landmark regions defined

• Proper heading structure

<a href="#main" class="skip-link">Skip to main content</a>
<main id="main">...</main>

2.4.2 Page Titled (Level A)

• Unique, descriptive page titles

• Title reflects page content

2.4.3 Focus Order (Level A)

• Focus order matches visual order

• tabindex used correctly

2.4.4 Link Purpose (In Context) (Level A)

• Links make sense out of context

• No "click here" or "read more" alone

<!-- Bad -->
<a href="report.pdf">Click here</a>

<!-- Good -->
<a href="report.pdf">Download Q4 Sales Report (PDF)</a>

2.4.6 Headings and Labels (Level AA)

• Headings describe content

• Labels describe purpose

2.4.7 Focus Visible (Level AA)

• Focus indicator visible on all elements

• Custom focus styles meet contrast

:focus {
  outline: 3px solid #005fcc;
  outline-offset: 2px;
}

2.4.11 Focus Not Obscured (Level AA) - WCAG 2.2

• Focused element not fully hidden

• Sticky headers don't obscure focus

### Understandable (Principle 3)

```markdown
## 3.1 Readable

### 3.1.1 Language of Page (Level A)
- [ ] HTML lang attribute set
- [ ] Language correct for content

```html
<html lang="en">

3.1.2 Language of Parts (Level AA)

• Language changes marked

<p>The French word <span lang="fr">bonjour</span> means hello.</p>

3.2 Predictable

3.2.1 On Focus (Level A)

• No context change on focus alone

• No unexpected popups on focus

3.2.2 On Input (Level A)

• No automatic form submission

• User warned before context change

3.2.3 Consistent Navigation (Level AA)

• Navigation consistent across pages

• Repeated components same order

3.2.4 Consistent Identification (Level AA)

• Same functionality = same label

• Icons used consistently

3.3 Input Assistance

3.3.1 Error Identification (Level A)

• Errors clearly identified

• Error message describes problem

• Error linked to field

<input aria-describedby="email-error" aria-invalid="true" />
<span id="email-error" role="alert">Please enter valid email</span>

3.3.2 Labels or Instructions (Level A)

• All inputs have visible labels

• Required fields indicated

• Format hints provided

3.3.3 Error Suggestion (Level AA)

• Errors include correction suggestion

• Suggestions are specific

3.3.4 Error Prevention (Level AA)

• Legal/financial forms reversible

• Data checked before submission

• User can review before submit

### Robust (Principle 4)

```markdown
## 4.1 Compatible

### 4.1.1 Parsing (Level A) - Obsolete in WCAG 2.2
- [ ] Valid HTML (good practice)
- [ ] No duplicate IDs
- [ ] Complete start/end tags

### 4.1.2 Name, Role, Value (Level A)
- [ ] Custom widgets have accessible names
- [ ] ARIA roles correct
- [ ] State changes announced

```html
<!-- Accessible custom checkbox -->
<div role="checkbox"
     aria-checked="false"
     tabindex="0"
     aria-labelledby="label">
</div>
<span id="label">Accept terms</span>

4.1.3 Status Messages (Level AA)

• Status updates announced

• Live regions used correctly

<div role="status" aria-live="polite">3 items added to cart</div>

<div role="alert" aria-live="assertive">Error: Form submission failed</div>

## Automated Testing

```javascript
// axe-core integration
const axe = require('axe-core');

async function runAccessibilityAudit(page) {
  await page.addScriptTag({ path: require.resolve('axe-core') });

  const results = await page.evaluate(async () => {
    return await axe.run(document, {
      runOnly: {
        type: 'tag',
        values: ['wcag2a', 'wcag2aa', 'wcag21aa', 'wcag22aa']
      }
    });
  });

  return {
    violations: results.violations,
    passes: results.passes,
    incomplete: results.incomplete
  };
}

// Playwright test example
test('should have no accessibility violations', async ({ page }) => {
  await page.goto('/');
  const results = await runAccessibilityAudit(page);

  expect(results.violations).toHaveLength(0);
});

# CLI tools
npx @axe-core/cli https://example.com
npx pa11y https://example.com
lighthouse https://example.com --only-categories=accessibility

Remediation Patterns

Fix: Missing Form Labels

<!-- Before -->
<input type="email" placeholder="Email" />

<!-- After: Option 1 - Visible label -->
<label for="email">Email address</label>
<input id="email" type="email" />

<!-- After: Option 2 - aria-label -->
<input type="email" aria-label="Email address" />

<!-- After: Option 3 - aria-labelledby -->
<span id="email-label">Email</span>
<input type="email" aria-labelledby="email-label" />

Fix: Insufficient Color Contrast

/* Before: 2.5:1 contrast */
.text {
  color: #767676;
}

/* After: 4.5:1 contrast */
.text {
  color: #595959;
}

/* Or add background */
.text {
  color: #767676;
  background: #000;
}

Fix: Keyboard Navigation

// Make custom element keyboard accessible
class AccessibleDropdown extends HTMLElement {
  connectedCallback() {
    this.setAttribute("tabindex", "0");
    this.setAttribute("role", "combobox");
    this.setAttribute("aria-expanded", "false");

    this.addEventListener("keydown", (e) => {
      switch (e.key) {
        case "Enter":
        case " ":
          this.toggle();
          e.preventDefault();
          break;
        case "Escape":
          this.close();
          break;
        case "ArrowDown":
          this.focusNext();
          e.preventDefault();
          break;
        case "ArrowUp":
          this.focusPrevious();
          e.preventDefault();
          break;
      }
    });
  }
}

Best Practices

Do's

• Start early - Accessibility from design phase

• Test with real users - Disabled users provide best feedback

• Automate what you can - 30-50% issues detectable

• Use semantic HTML - Reduces ARIA needs

• Document patterns - Build accessible component library

Don'ts

• Don't rely only on automated testing - Manual testing required

• Don't use ARIA as first solution - Native HTML first

• Don't hide focus outlines - Keyboard users need them

• Don't disable zoom - Users need to resize

• Don't use color alone - Multiple indicators needed

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