title: jQuery set ancestor element for scope
body: <p>I have a situation where all my selectors all have the same ancestor element</p>
  
  <pre><code>$('#foo .bar')...
  $('#foo .some_class')...
  $('#foo .some_other_class')...
  </code></pre>
  
  <p>I was wondering if there was a way to tell jQuery to always assume the selector will descend from <code>#foo</code>? So something like</p>
  
  <pre><code>$.ancestorWillAlwaysBe('#foo');
  $('.bar')...
  $('.some_class')...
  $('.some_other_class')...
  </code></pre>