title: Why does event instanceof TouchEvent throw an Exception in Firefox
body: <p>I am trying to run some code that works on chrome through firefox, but I get an exception.</p>
  
  <pre><code>document.onmousedown = function(e) { 
      try {
          if (e instanceof TouchEvent) {
              alert('haa');
          } 
      }
      catch (ex) {
          alert('hoo');
      }
  };
  </code></pre>
  
  <p>What should I use instead? the TouchEvent is in the mozilla documentation...</p>
  
  <p>jsFiddle <a href="http://jsfiddle.net/f7kxrvxh/" rel="nofollow">here</a></p>