You are looking at the HTML representation of the XML format.
HTML is good for debugging, but is unsuitable for application use.
Specify the format parameter to change the output format.
To see the non HTML representation of the XML format, set format=xml.
See the complete documentation, or API help for more information. 
<?xml version="1.0"?>
<api>
  <query-continue>
    <contributors pccontinue="3282|12880" />
  </query-continue>
  <query>
    <normalized>
      <n from="Main_Page" to="Main Page" />
    </normalized>
    <pages>
      <page pageid="3282" ns="0" title="Main Page" anoncontributors="2">
        <contributors>
          <user userid="1" name="Wikiadmin" />
          <user userid="2" name="Maxd" />
          <user userid="8" name="王德宇" />
          <user userid="22" name="Zhenchen" />
          <user userid="182" name="2013012178" />
          <user userid="2414" name="Wyf wiki" />
          <user userid="2582" name="Emma Peng" />
          <user userid="12108" name="Sunyq12" />
          <user userid="12573" name="第三专业学习小组" />
          <user userid="12844" name="Yanzeyu" />
        </contributors>
      </page>
    </pages>
  </query>
</api>