<!DOCTYPE html>
<html class="reftest-wait">
<!-- Test: if button has a custom error, it should not be affected by :valid
pseudo-class -->
<link rel='stylesheet' type='text/css' href='style.css'>
<body onload="document.getElementById('b').setCustomValidity('foo'); document.documentElement.className='';">
<button class='invalid' id='b'></button>
</body>
</html>