title: count immediate child elements using jquery with a variable
body: <p>This question is similar to this one (but not exact):
  <a href="https://stackoverflow.com/questions/250688/count-immediate-child-div-elements-using-jquery">Count immediate child div elements using jQuery</a></p>
  
  <p>I have a bunch of lists that represent christmas presents for different people. 
  As an example, this is a list of presents for one person. Note that new people can be added </p>
  
  <pre><code>&lt;ul id = "presents"&gt;
  &lt;li id = "person1" &gt;
  &lt;ul id = "presentsforperson1"&gt;
  &lt;li id = "present1" &gt;
  &lt;ul id = "present1info"&gt;
  &lt;li&gt; Present 1 &lt;/li&gt;
  &lt;li&gt; A New Pair of Shoes &lt;/li&gt;
  &lt;li&gt; $19.99 &lt;/li&gt;
  &lt;/ul&gt;
  &lt;/li&gt;
  &lt;!-- More presents for person 1 can be added here dynamically--&gt;
  &lt;/ul&gt;
  &lt;/li&gt;
  &lt;!-- More people can be added here --&gt;
  &lt;/ul&gt;
  </code></pre>
  
  <p>Unlike the question posted, I have the object presentsforperson1 in a variable called drop (droppable). I was wondering what the correct syntax is for finding the number of presents person 1 has (in this case 1) with this variable?</p>
  
  <p>This is what I have tried so far:</p>
  
  <pre><code> var numberofPresents = $(drop + "ul &gt; li").length; //drop holds li#presentsforperson1 .droppable
   var numberofPresents = $(dropid + "ul &gt; li").length; //dropID is $(drop).attr("id");
  </code></pre>