title: Setting PHP's default timezone
body: <p>In my web app, I let the users choose their preferred timezone from a list (that contains <a href="http://www.php.net/manual/en/timezones.php" rel="nofollow">all timezones that PHP supports</a>).</p>
  
  <p>Let's say that <code>$_POST['timezone']</code> is the chosen timezone (<em>e.g.</em> <code>America/New_York</code>).
  I set it with the following code which produces no errors:</p>
  
  <pre><code>default_date_timezone_set($_POST['timezone']);
  </code></pre>
  
  <p>But when I reload the page it goes back to what it was before (<em>e.g.</em> <code>Europe/Moscow</code>).
  Do I have to set the default timezone in every script or isn't the function (<code>default_date_timezone_set</code>) working properly?
  Thanks!</p>