Principle 3 Understandable · Guideline 3.3: Input Assistance
3.3.3 Error Suggestion
Where possible, suggest how to fix the error.
What this means in practice
Not just “invalid date” but “please use DD/MM/YYYY”. One sentence of effort, many abandoned forms saved.
Normative wording
The binding text lives at the W3C. What you read here is our own faithful rendering – not a quotation.