PHP 日期函数 date_default_timezone_set()

<?php
   echo "Old time zone is ". date_default_timezone_get(). "\n";

   $timeZone = 'America/Costa_Rica';

   if( date_default_timezone_set( $timeZone) ){
      # Now get this time zone.
      echo "New time zone is ". date_default_timezone_get(). "\n";
   }
?>