Robust Principle

Definition

Content must be robust enough to be reliably interpreted by a wide variety of user agents, including assistive technologies.

Key Points

1. Compatibility

• Valid HTML
• Proper ARIA implementation
• Assistive technology support

<!-- Good example -->
<button role="tab" aria-selected="true" aria-controls="panel-1">Tab 1</button>
<!-- Bad example -->
<div onclick="handleTab()">Tab 1</div>

2. Parsing

• Well-formed tags
• Unique IDs
• No duplicate attributes

<!-- Good example -->
<div id="unique-id">
  <p>Structured content</p>
</div>
<!-- Bad example -->
<div id="duplicate-id">
  <p>First element</p>
</div>
<div id="duplicate-id">
  <p>Second element</p>
</div>

3. Name and Role

• Custom components with appropriate roles
• Accessible names for all interactive elements
• Communicated states and properties

<div role="alertdialog" aria-labelledby="dialog-title" aria-describedby="dialog-desc">
  <h2 id="dialog-title">Confirmation</h2>
  <p id="dialog-desc">Do you want to continue?</p>
</div>

Robustness Testing

1. HTML validation
2. Cross-browser testing
3. Assistive technology testing
4. ARIA role verification