principle: Understandable
Make sure that everyone can understand or comprehend the same content and components. Can people understand this content with whatever capacity they have?
3.2.5 Change on Request
Major changes (like open dialog, navigate, submit) must only happen when explicitly requested.
3.2.6 Consistent Help
Help options (like contact link, support widget) must appear in the same place across pages.
3.3.1 Error Identification
Errors and validation must be clearly identified and described in text, not just visually (like color or highlighting).
3.3.2 Labels or Instructions
Form fields must have clear labels or instructions to avoid confusion and help complete the input correctly.
3.3.3 Error Suggestion
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”).
3.3.4 Error Prevention (Legal, Financial, Data)
Before submitting important actions (like payments or legal forms), the form must allow reviewing the input, correcting mistakes, or confirming.
3.3.5 Help
Provide additional help (like text instructions, help links, or tooltips) when label alone might be ambiguous or confusing.
3.3.6 Error Prevention (All)
Before submitting, all forms must allow reviewing the input, correcting mistakes, or confirming.
3.3.7 Redundant Entry
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.
3.3.8 Accessible Authentication (Minimum)
Authentication must not rely on memory alone. Allow copy-paste, password managers, or other options (like email verification).
