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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>
    <allimages gaicontinue="18_2_meshTriangle_concurrentRepresentation_20180227.jpg" />
  </query-continue>
  <query>
    <pages>
      <page pageid="323" ns="6" title="File:18 2 MeshQualityOptions 20180227.jpg" />
      <page pageid="317" ns="6" title="File:18 2 TelemacSimulationSettings 20180227.jpg" />
      <page pageid="318" ns="6" title="File:18 2 TelemacSimulation 20180227.jpg" />
      <page pageid="322" ns="6" title="File:18 2 TriangulationOptions 20180227.jpg" />
      <page pageid="320" ns="6" title="File:18 2 aCuteUsage 20180227.jpg" />
      <page pageid="321" ns="6" title="File:18 2 conceptualMeshData 20180227.jpg" />
      <page pageid="325" ns="6" title="File:18 2 crossSectionManagementCenterExample 20180227.jpg" />
      <page pageid="324" ns="6" title="File:18 2 crossSectionManagement 20180227.jpg" />
      <page pageid="316" ns="6" title="File:18 2 dragAndDrop 20180227.jpg" />
      <page pageid="327" ns="6" title="File:18 2 environmentVariable 20180227.jpg" />
    </pages>
  </query>
</api>