title: select elements from a specified html string
body: <p>All, Say you have a Html string like below. I want to select all the <code>li</code> element from it, and append them to a <code>ul</code>.</p>
  
  <pre><code>var sHtml="&lt;li&gt;..&lt;/li&gt;&lt;li&gt;..&lt;/li&gt;&lt;li&gt;..&lt;/li&gt;&lt;li&gt;..&lt;/li&gt;&lt;span&gt;xxx&lt;/span&gt;";
  $("#myUl").append($("li",$(sHtml)));
  </code></pre>
  
  <p>But this code doesn't work . Is there any way to make it using jquery?</p>