title: Jquery Chaining vs Callbacks
body: <p>For jQuery, what's the difference in the outcome of the following two snippets. Anything? Am I correct that the callback and the second item in the chain are both executed upon completion of the first animation?</p>
  
  <pre><code>$(selector).animate({ opacity: 1 }).animate({ opacity: 0.5 });
  </code></pre>
  
  <p>vs</p>
  
  <pre><code>$(selector).animate({ opacity: 1}, function()
  {
      $(this).animate({ opacity: 0.5 });
  });
  </code></pre>
  
  <p>In what type(s) of situation would I want to use one over the other? Would I only use the latter if I needed to do something more sophisticated or switch to a different selector?</p>
  
  <p>Thanks in advance.</p>