title: .filter() return undefined
body: <p>I have a problem with <code>.filter()</code> for the data returned from <code>$.get()</code>.</p>
  
  <pre><code>$.get(url, function(data){
    $(data).filter('[ref=A]').html() // return undefined
  });
  </code></pre>
  
  <p>HTML</p>
  
  <pre><code>&lt;span ref='B'&gt;&lt;span ref='A'&gt;abc&lt;/span&gt;&lt;/span&gt;
  </code></pre>
  
  <p>If I do</p>
  
  <pre><code> $(data).filter('[ref=B]').html() // return &lt;span ref='A'&gt;abc&lt;/span&gt;
  </code></pre>
  
  <p>After removing <code>&lt;span ref="B"&gt;</code> and do</p>
  
  <pre><code>$(data).filter('[ref=A]').html()// return abc
  </code></pre>
  
  <p>My question is how can I get the HTML abc with tag <code>&lt;span ref="B"&gt;</code>?</p>
  
  <p>Did I use filter() incorrectly? Please advise.</p>