Investigate setCustomValidity ValidityState APIs

[staabm]

modern browsers allow to propagate the valid/invalid state of native element via setCustomValidity ValidityState APIs.
In combination with css pseudo-selector :invalid this could shrink the size of our lib and the markup changes after validation to a minimum.

we should check whether we can apply our feature set to this api and drop the redundant functionality

see
https://developer.mozilla.org/en-US/docs/Web/Guide/HTML/HTML5/Constraint_validation#Constraint_validation_process

https://developer.mozilla.org/en-US/docs/Web/Guide/HTML/HTML5/Constraint_validation#Constraint_API%27s_element.setCustomValidity()

https://developer.mozilla.org/en-US/docs/Web/API/ValidityState

[jimmywarting]

👍

In fav. of using the built in constraint validation.
required is one such thing that you for instance don't need translation for...
you can get a localized message with this api for instance:

const i = document.createElement('input')
i.required = true
i.validationMessage

...and support so many more languages