title: use javascript to find parameter in url and then apply if then logic
body: <p>I am trying to make my page perform an action only if it sees that a particular parameter is present in the url.</p>
  
  <p>I essentially want the javascript code to do this:</p>
  
  <p>consider an example page such as: <a href="http://www.example.com?track=yes" rel="noreferrer">http://www.example.com?track=yes</a></p>
  
  <p>If a page loads that contains the parameter 'track' within the url, print 'track exists', else if the 'track' parameter doesn't exist print 'track does not exist'</p>