title: Can a single MutationObserver object observe multiple targets?
body: <p>I would like to use a <a href="https://developer.mozilla.org/en-US/docs/Web/API/MutationObserver"><code>MutationObserver</code></a> object to observe changes to some of my DOM nodes. </p>
  
  <p>The docs give an example of creating a <code>MutationObserver</code> object and registering it on a target. </p>
  
  <pre><code>// select the target node
  var target = document.querySelector('#some-id');
  
  // create an observer instance
  var observer = new MutationObserver(function(mutations) {
    mutations.forEach(function(mutation) {
      console.log(mutation.type);
    });    
  });
  
  // configuration of the observer:
  var config = { attributes: true, childList: true, characterData: true };
  
  // pass in the target node, as well as the observer options
  observer.observe(target, config);
  </code></pre>
  
  <hr>
  
  <p>Say I have the code above, but just under it, I place this code:</p>
  
  <pre><code>var target2 = document.querySelector('#some-other-id');
  var config2 = {attributes: true, subtree: true};
  observer.observe(target2, config2);
  </code></pre>
  
  <p>Will <code>observer</code>: </p>
  
  <ul>
  <li>now be observing 2 targets?</li>
  <li>will it stop observing <code>target</code>?</li>
  <li>will it decide not to observe <code>target2</code>?</li>
  <li>will it throw an error?</li>
  <li>or will it exhibit some other behavior?</li>
  </ul>