Success criterion 3.1.1 Language of Page
Level Level A, WCAG principle: Understandable
Assigned to the following themes: CODE AND LABELS WORDING
Each page must have a <html lang=""> attribute that matches the main language of the page.
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WCAG Explorer (beta)
This resource is designed for anyone eager to master digital accessibility. Explore WCAG success criteria through clear, easy-to-understand descriptions. We owe a special "hat tip" to Johannes Lehner’s WCAG Card Deck, which served as the inspiration for this project.
We plan to expand this library over time, so please check back regularly for updates.
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13 success criteria found for Level A + AA and Understandable principle and
Success criterion 3.2.1 On Focus
Level Level A, WCAG principle: Understandable
Assigned to the following themes: KEYBOARD
No unexpected changes must happen when an element receives focus (like open a popup, move focus, submit a form).
Success criterion 3.2.2 On Input
Level Level A, WCAG principle: Understandable
Assigned to the following themes: CODE AND LABELS FORMS KEYBOARD
No unexpected changes must happen when a field value changes (like auto-submit, reload, open new page).
Success criterion 3.2.6 Consistent Help [2.2 only]
Level Level A, WCAG principle: Understandable
Assigned to the following themes: WHOLE SITE
Help options (like contact link, support widget) must appear in the same place across pages.
Success criterion 3.3.1 Error Identification
Level Level A, WCAG principle: Understandable
Assigned to the following themes: FORMS WORDING
Errors and validation must be clearly identified and described in text, not just visually (like color or highlighting).
Success criterion 3.3.2 Labels or Instructions
Level Level A, WCAG principle: Understandable
Assigned to the following themes: CODE AND LABELS FORMS
Form fields must have clear labels or instructions to avoid confusion and help complete the input correctly.
Success criterion 3.3.7 Redundant Entry (2.2 only)
Level Level A, WCAG principle: Understandable
Assigned to the following themes: FORMS
Don't ask for the same information twice in the same process.
Provide pre-filled fields or selection options if the information was already given.
Success criterion 3.1.2 Language of Parts
Level Level AA, WCAG principle: Understandable
Assigned to the following themes: CODE AND LABELS WORDING
Any parts of the content in a different language must be marked with the correct lang attribute.
Expressions borrowed from another language (like "déjà vu" in English) do not need this, unless pronunciation or understanding would be affected.
Success criterion 3.2.3 Consistent Navigation
Level Level AA, WCAG principle: Understandable
Assigned to the following themes: WHOLE SITE
Navigation elements (like menus, links, search) must appear in the same place and order across pages.
Success criterion 3.2.4 Consistent Identification
Level Level AA, WCAG principle: Understandable
Assigned to the following themes: WHOLE SITE
Elements with the same function must look, behave, and be labeled the same way across pages.
Success criterion 3.3.3 Error Suggestion
Level Level AA, WCAG principle: Understandable
Assigned to the following themes: FORMS WORDING
Errors and validation messages must show text that:
- explains the problem and
- gives suggestions for how to fix it (like "enter at least 8 characters")
Success criterion 3.3.4 Error Prevention (Legal, Financial, Data)
Level Level AA, WCAG principle: Understandable
Assigned to the following themes: FORMS WORDING
Important forms like a legal agreement or submitting financial information offer the opportunity to check the information entered before sending.
Success criterion 3.3.8 Accessible Authentication (Minimum) [2.2 only]
Level Level AA, WCAG principle: Understandable
Assigned to the following themes: FORMS
Authentication must not rely on memory alone.
Allow copy-paste, password managers, or other options (like email verification).