title: Get all possible $_GET parameters from URL
body: <p>I have link to a website that runs a php code with the following variable:<br>
  <code>http://www.example.com/run.php?test=abc</code></p>
  
  <p>There are other $_GET variables usable in the link other than <code>test</code>, say <code>id</code> and <code>title</code>, which I don't know about. Is it possible to get the missing variables (If there are any)? In my example case it would be the <code>id</code> and <code>title</code> variables.</p>