When there is an error in the input contents, it is desirable to explain how to correct it. However, in the case of Understanding WCAG 2.0, we cite the case of "Please enter January" to the user who entered "12" for "Please enter month", but this is not a very good case I think. Rather, say "Please enter with alphabet (aZ) and number (0-9)" to issue an error if you are entering in half-width alphanumeric input for double-byte characters, It is better to refer to the perimeter (it is better to convert it to half-width alphanumeric characters by accepting input without issuing an error, but it will reduce user's effort, but such correspondence depends on case).
The difference from 3.3.1 is a bit hard to understand, but the subject of 3.3.1 is to specify the error part and not to clarify how to correct the error.
Also, it is said that it is desirable to give a link to an error part even in 3.3.1 or 3.3.3.
|Principle||Understandable||Information and the operation of user interface must be understandable.|
|Guideline||Input Assistance||Help users avoid and correct mistakes.|
|If an input error is detected automatically and you can suggest a correction method, that suggestion is presented to the user. However, excluding cases where the purpose of security or content is impaired.|