title: classList.toggle doesn't work in Firefox
body: <p>I have noticed that toggling class in Firefox is not working and I'm not sure why.</p>
  
  <pre><code>var contactUs = document.querySelectorAll('.contact-us')[0];
  
  var buttonExpand = document.querySelectorAll('a.write')[0];
  buttonExpand.addEventListener('click', function(e) {
      contactUs.classList.toggle('js-expand-form');
      console.log('click');
  },false);
  </code></pre>
  
  <p>When I click on <code>a.write</code> in Firefox nothing happens. It works on Chrome and IE.<br><br>
  The problem is related both to event binding and to <code>classList.toggle</code>, because <code>console.log('click')</code> doesn't work in FF and when I type manually from console:</p>
  
  <pre><code>document.querySelectorAll('.contact-us')[0].classList.toggle('js-expand-form')
  </code></pre>
  
  <p>it returns true or false but nothing actually changes - inspected element doesn't get a new class. <br>What concerns me even more is that the same line pasted in Chrome's console doesn't take effect either, despite the fact it works in normal circumstances.<br><br>
  jQuery's equivalent <code>jQuery('.contact-us').toggleClass('js-expand-form')</code> works in every browser, including pasting into console.</p>
  
  <p>See <a href="http://jsfiddle.net/Lh3t7pbv/4/" rel="nofollow">the fiddle</a>.</p>