title: How to use MutationObserver?
body: <p>I recently came across this awesome <code>MutationObserver</code> feature which sort of keep tracks of the changes on any dom element. I used the code that was shown on the mozilla developer network, but can't seem to make it run. This is the code I used (<a href="http://jsfiddle.net/6Jajs/" rel="noreferrer">link</a>):</p>
  
  <pre><code>   // create an observer instance
  var target = document.querySelector('#something');
  console.log(target);
  var observer = new WebKitMutationObserver(function(mutations) {
      mutations.forEach(function(mutation) {
        console.log("Success");
          //$('#log').text('input text changed: "' + target.text() + '"');
          //console.log(mutation, mutation.type);
      });    
  });
  observer.observe(target, { attributes: true, childList: true, characterData: true });
  //observer.disconnect(); - to stop observing
  
  // test case
  setInterval(function(){
      document.querySelector('#something').innerHTML = Math.random();
  },1000);
  </code></pre>
  
  <p>The above code doesn't seems to work. However if I modify the same code with a bit of jQuery, everything seems to work just fine (Demo <a href="http://jsfiddle.net/hZKP2/149/" rel="noreferrer">here</a>). Is there something I'm missing from the docs or I'm just misinterpreting the observer feature.</p>