You are looking at the HTML representation of the XML format.
HTML is good for debugging, but probably is not suitable for your application.
See complete documentation, or API help for more information. 
<?xml version="1.0"?>
<api>
  <query>
    <allpages>
      <p pageid="15841" ns="0" title="B11111" />
      <p pageid="15859" ns="0" title="B22222" />
      <p pageid="13933" ns="0" title="BACKGROUND" />
      <p pageid="1962" ns="0" title="BRAINSTORMING" />
      <p pageid="4405" ns="0" title="Back to Main Page" />
      <p pageid="10867" ns="0" title="Beijing Normal/10 August 2008" />
      <p pageid="10542" ns="0" title="Beijing Normal/10 October 2008" />
      <p pageid="10868" ns="0" title="Beijing Normal/11 August 2008" />
      <p pageid="10543" ns="0" title="Beijing Normal/11 October 2008" />
      <p pageid="10869" ns="0" title="Beijing Normal/12 August 2008" />
    </allpages>
  </query>
  <query-continue>
    <allpages apfrom="Beijing Normal/12 October 2008" />
  </query-continue>
</api>