jQuery methods, order of optional arguments
<p>I just played around a bit with the <a href="http://api.jquery.com/animate/" rel="nofollow">animate()</a> method.</p>

<blockquote>
  <p>.animate( properties [, duration] [, easing] [, complete] )</p>
</blockquote>

<p>I know that I dont have to pass all the arguments to a function in javascript. But what I would like to know is how jquery figures out that <code>function(){ }</code> refers to the callback function, which is actually the 4:th parameter, instead of the easing string (which is the 3:rd)?</p>

<pre><code>$('div').animate({ height: '10px' }, 100, function(){ });
</code></pre>
