Forms Accessibility Best Practices

This document defines project-level requirements for accessible form design, validation, and error handling.

1. Core Principle

All users must be able to understand, complete, and submit forms with assistive technologies, keyboard-only input, and varying cognitive needs.

2. Labels and Instructions

• Every form control must have a programmatically associated label.
• Placeholder text must not be used as the only label.
• Required fields must be identified in text, not by color alone.
• Provide concise instructions before complex input groups.

3. Grouping and Structure

• Use fieldset and legend for related controls (for example, radio groups).
• Keep visual and semantic grouping aligned.
• Use headings to separate long forms into clear sections.

4. Input Purpose and Autocomplete

• Use appropriate input types (email, tel, number, date) where valid.
• Add autocomplete values for common user data when appropriate.
• Avoid input patterns that block paste or standard keyboard actions.

5. Validation and Error Messaging

• Validate on submit at minimum; avoid disruptive real-time validation.
• Error messages must be specific and actionable.
• Error text must be programmatically associated with the invalid field.
• Mark invalid controls with aria-invalid="true" when applicable.
• Do not rely on color alone to indicate errors.

6. Error Summary Pattern

For multi-error submissions:

• Show an error summary near the top of the form.
• Move focus to the error summary after failed submit.
• Each summary item should link to the corresponding field.

7. Success, Status, and Async Feedback

• Announce submission status and async validation outcomes to assistive tech.
• Use polite live regions for non-critical updates.
• Use assertive announcements only for blocking failures.

8. Time Limits and Session Expiry

• Warn users before timeout when possible.
• Provide a way to extend session time for critical workflows.
• Preserve entered data when safe and feasible.

9. Testing Expectations

Minimum checks for each form change:

• Navigate and complete the form using keyboard only.
• Verify screen reader announces labels, required state, and errors correctly.
• Submit with invalid inputs and confirm clear recovery paths.
• Confirm focus moves to error summary and then to each field link target.

10. Definition of Done

A form change is complete only when:

• All controls have accessible names.
• Validation and error recovery are understandable and navigable.
• Keyboard and screen reader workflows pass manual checks.
• No blocking accessibility defects remain.