title: Use Query String in XML File
body: <p>Is it possible to use a query string inside an XML file?</p>
  
  <p>I did not think it was possible and then I saw a url like this <code>http://site.com/file.xml?tag=howdoiusethis</code></p>
  
  <p>I can think of a lot of ways that this could be useful, but it is a new concept to me and I am not finding any information on how to use this tag/ query string in the document. Ideally I would like to use it to filter out the xml that is readable in the document for the given tag/ query string.</p>
  
  <p>Thanks</p>