<!DOCTYPE html>
<html>
  <!-- Test: if select is required and the selected option has an empty
             string value and the selection didn't changed,
             :-moz-ui-invalid should not apply. -->
  <link rel='stylesheet' type='text/css' href='style.css'>
  <body>
    <select class='notinvalid' required>
      <option value="">foo</option>
    </select>
  </body>
</html>