title: HTMLPurifier - adding to ignore list
body: <p>I am trying to pass some XML tags (abcdef>) through htmlpurifier. Since the tags itself are not supported, I am trying to add an element first and then adding it to allowedElements. However this is not working, i'm just getting a blank page. Any ideas please on what I am doing wrong, or if there is an easier way to achieve what i am looking for.</p>
  
  <pre><code>$config = HTMLPurifier_Config::createDefault();
  $config-&gt;set('Core', 'Encoding', "UTF-8");
  $config-&gt;set('HTML', 'DefinitionID', 'pinaki-test');
  $config-&gt;set('HTML', 'DefinitionRev', 3);
  $config-&gt;set('Cache', 'DefinitionImpl', null); // remove this later!
  $config-&gt;set('Cache', 'SerializerPath', "/var/cache/htmlpurify");
  $def = $config-&gt;getHTMLDefinition(true);
  $def-&gt;addElement("tag1", false, 'Empty', 'Common', array());
  $def-&gt;addElement("tag2", false, 'Empty', 'Common', array());
  $config-&gt;set('HTML', 'AllowedElements', array("tag1", "tag2"));
  </code></pre>
  
  <p>Let know if anyone needs any other details.</p>
  
  <p><strong>Note:</strong> The library is working fine without adding the elements.</p>