Better Invalid Input Selectors
(thanks @joao6246 invalid input in CSS state/selector)
https://css-tricks.com/form-validation-ux-html-css/#aa-sub-trick-testing-if-an-input-has-a-value-or-not
https://css-tricks.com/form-validation-ux-html-css/#aa-sub-trick-testing-if-an-input-has-a-value-or-not
CSS-TricksChris Coyier
You can do an impressive amount of form validation with just HTML attributes. You can make the user experience pretty clean and clear with CSS selectors. But
