<!DOCTYPE html> <html class="reftest-wait"> <!-- Test: if button is not disabled, it is candidate for constraint validation and should be affected by :valid pseudo-class. --> <link rel='stylesheet' type='text/css' href='style.css'> <body onload="document.getElementById('b').removeAttribute('disabled'); document.documentElement.className='';"> <button class='valid' id='b' disabled></button> </body> </html>