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HTML is good for debugging, but probably is not suitable for your application.
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<?xml version="1.0"?>
<api>
  <query>
    <allusers>
      <u userid="4" name="Yura001" />
      <u userid="13" name="Арсений" />
      <u userid="11" name="Колодочкин" />
      <u userid="2" name="Марина Авраменко" />
    </allusers>
  </query>
</api>