<!DOCTYPE html> <html> <!-- Test: if textarea has a disabled fieldset ancestor, it is barred from constraint validation and should not be affected by :-moz-ui-invalid pseudo-class. --> <link rel='stylesheet' type='text/css' href='style.css'> <body> <fieldset disabled> <fieldset> <textarea class='notinvalid' required></textarea> </fieldset> </fieldset> </body> </html>