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