<!DOCTYPE html> <html class="reftest-wait"> <head> <script> function doTest() { document.getElementById('t').removeAttribute('readonly'); document.documentElement.className=''; } document.addEventListener("MozReftestInvalidate", doTest); </script> </head> <!-- Test: if textarea is no longer readonly, it is candidate for constraint validation and should be affected by :invalid pseudo-class. --> <link rel='stylesheet' type='text/css' href='style.css'> <body> <textarea class='invalid' id='t' readonly required></textarea> </body> </html>