title: ISSET and GET in PHP
body: <p>Is this an efficient way of converting the url ?p=XX to displayed content?</p>
  
  <p><code>&lt;?php if (isset($p[include ($_GET['p'] . '.php')])) ?&gt;</code></p>
  
  <hr>
  
  <p>Other bonus question:</p>
  
  <p>I'm using xampp, why cant I use the <code>&lt;?</code> or <code>&lt;?=</code> tags rather than <code>&lt;?php</code> and <code>&lt;?php echo</code> respectively.</p>