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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>
    <allpages gapcontinue="The_Sunjammer_Project" />
  </query-continue>
  <query>
    <pages>
      <page pageid="1284" ns="0" title="Tacking Solar Sails" touched="2009-06-30T15:19:43Z" lastrevid="3850" counter="46835" length="2017" />
      <page pageid="3014" ns="0" title="The Mote in God&#039;s Eye" touched="2014-10-27T20:11:19Z" lastrevid="4443" counter="10847" length="498" />
      <page pageid="1282" ns="0" title="The Physics of Solar Sailing" touched="2009-06-30T15:19:43Z" lastrevid="3849" counter="40167" length="10328" />
      <page pageid="3022" ns="0" title="The Starflight Handbook: a Pioneers Guide to Interstellar Travel" touched="2014-10-27T20:12:37Z" lastrevid="4444" counter="11182" length="630" />
    </pages>
  </query>
</api>