WCAG 3.3.3: Error Suggestion
WCAG 3.3.3 Error Suggestion is a level AA success criterion from WCAG 2.0. If an error is detected and a suggestion is known, it is provided, unless it would risk security or the purpose of the field.
People need to know how to fix the field, not only that it failed.
How to test
Enter a bad email. The message should say what format is expected.
How to fix
Add a suggestion: include the @ and a domain.
Example that fails
The message says Invalid.
Example that passes the check
The message says Enter an email like [email protected].
Shopify
Write specific error text in custom forms.
WooCommerce
Customise WooCommerce validation messages so they say how to fix the field.
WordPress
Set the form plugin error to include an example.
Wix
Edit the field error text so it includes an example.