title: jquery selector question: do something only if all elements are hidden
body: <p>I need to do something only if all the li's in a given ul are hidden.. this doesn't seem to do the trick. is there a way?</p>
  
  <pre><code>if ($('#some_ul li:hidden')) {
    // do something only if all 'li's in a given ul are hidden
  }
  </code></pre>