title: CSS nth-match doesn't work
body: <p>nth-match is supposed to work in jsfiddle following way</p>
  
  <pre><code>:nth-match(even of p,h3) {text-decoration: underline;}
  </code></pre>
  
  <p>this should underline every second <code>p</code> and <code>h3</code> elements. But, it doesn't work - neither in FF nor in Chrome: </p>
  
  <p><a href="http://jsfiddle.net/VUKQS/" rel="noreferrer">http://jsfiddle.net/VUKQS/</a></p>
  
  <p>Where's the problem?</p>