Validation States

Validation states provide visual feedback to users about the validity of form input.

Use the aria-invalid attribute to indicate validation state:

• aria-invalid="true" — Indicates the field has failed validation
• aria-invalid="false" — Indicates the field has passed validation

Pair with aria-describedby to link helper text that explains the validation result:

<input
  type="email"
  aria-invalid="true"
  aria-describedby="email-error"
/>
<small id="email-error">Please enter a valid email address.</small>

Form Validation Example

<form>
  <fieldset>
    <label>
      Email address
      <input
        type="email"
        name="email"
        placeholder="user@example.com"
        aria-invalid="false"
        aria-describedby="email-helper"
        required
      />
      <small id="email-helper">We'll never share your email with anyone else.</small>
    </label>

    <label>
      Password
      <input
        type="password"
        name="password"
        aria-invalid="true"
        aria-describedby="password-helper"
        required
      />
      <small id="password-helper">Password must be at least 8 characters long.</small>
    </label>
  </fieldset>

  <input type="submit" value="Sign Up" />
</form>

INFO

The <small> element associated with a form control via aria-describedby automatically inherits the validation state colors.

Best Practices

Accessibility First

• Always use aria-invalid to communicate state to assistive technologies
• Pair with aria-describedby to provide context for the validation state
• Ensure error messages are clear and actionable

Visual Feedback

• Use the :invalid and :valid pseudo-classes for native HTML5 validation
• Combine with aria-invalid for JavaScript-driven validation
• Helper text (<small>) below form controls inherits validation colors automatically

Progressive Enhancement

1. Start with HTML5 validation attributes (required, type, pattern)
2. Enhance with JavaScript validation for complex rules
3. Use aria-invalid to communicate custom validation results

Reference

For detailed implementation of aria-invalid on specific elements, see the [aria-invalid] documentation.