Intent
The intent of this Success Criterion is to ensure that users are aware that an error
has occurred and can determine what is wrong. The error message should be as specific
as possible.
In the case of an unsuccessful form submission, re-displaying the form and indicating
the fields in error is insufficient for some users to perceive that an error has occurred.
Screen reader users, for example, will not know there was an error until they encounter
one of the indicators. They may abandon the form altogether before encountering the
error indicator, thinking that the page simply is not functional. Per the definition
in WCAG 2.0, an “input error” is information provided by the user
that is not accepted. This includes:
- information that is required by the web page but omitted by the user, or
- information that is provided by the user but that falls outside the required data
format [...]