title: Best way to find out if element is a descendant of another
body: <p>I am in the process of implementing jQuery, and taking out Prototype libraries in my codebase, and I am wondering if you could give me the best way to implement this functionality in jQuery.
  I am familiar with the jQuery ancestor<code>&gt;</code>descendant syntax, but just want to check if an element is a descendant by true of false, like the code below:
  can someone give me the most efficient jQuery solution for this ?</p>
  
  <pre><code>&lt;div id="australopithecus"&gt;
    &lt;div id="homo-herectus"&gt;
      &lt;div id="homo-sapiens"&gt;&lt;/div&gt;
    &lt;/div&gt;
  &lt;/div&gt;
  
  $('homo-sapiens').descendantOf('australopithecus');
  // -&gt; true
  
  $('homo-herectus').descendantOf('homo-sapiens');
  // -&gt; false
  </code></pre>