aria-invalid
Widget attributes might be mapped by a user agent to platform accessibility API state, for access by assistive technologies, or they might be accessed directly from the DOM. User agents MUST provide a way for assistive technologies to be notified when states change, either through DOM attribute change events or platform accessibility API events.
Indicates the entered value does not conform to the format expected by the application. See related aria-errormessage.
If the value is computed to be invalid or out-of-range, the application author SHOULD set this attribute to true. User agents SHOULD inform the user of the error. Application authors SHOULD provide suggestions for corrections if they are known.
When the user attempts to submit data involving a field for which aria-required is true, authors MAY use the aria-invalid attribute to signal there is an error. However, if the user has not attempted to submit the form, authors SHOULD NOT set the aria-invalid attribute on required widgets simply because the user has not yet entered data.
For future expansion, the aria-invalid attribute is an enumerated type. Any value not recognized in the list of allowed values MUST be treated by user agents as if the value true had been provided. If the attribute is not present, or its value is false, or its value is an empty string, the default value of false applies.