title: .find on jQuery giving me NaN
body: <p>I have a xml file . </p>
  
  <p>The structure is</p>
  
  <pre><code>&lt;library&gt;
  &lt;book&gt;
  &lt;title ISBN="12345"&gt;book title 1&lt;/title&gt;
  &lt;/book&gt;
  &lt;book&gt;
  &lt;title  ISBN="234567"&gt;book title 2&lt;/title&gt;
  &lt;/book&gt;
  ......
  &lt;/library&gt;
  </code></pre>
  
  <p>I am trying the following code to put the titles somewhere in my html:</p>
  
  <pre><code>$(xml).find("book").each( function(){           
              $("#content0").append($(this).find("title").text();
          } );
  </code></pre>
  
  <p>It is only giving me NaN . What am I doing wrong? (other values from xml is showing fine)</p>