title: jQuery: Given a selector, find only its visible elements
body: <p>This should be an easy one. I have a variable that I've already declared called $listItems. The declaration looks like this:</p>
  
  <pre><code>var $listItems = $ul.children('li'); // $ul is just a selected unordered list
  </code></pre>
  
  <p>Later in my code, I'd like to only get the ones that are currently visible. How would I go about that? Something like:</p>
  
  <pre><code>$listItems.parent().children(':visible')?
  </code></pre>
  
  <p>Thanks.</p>