Do you think it is preferred to use $_SERVER['DOCUMENT_ROOT']
in website's include
statements? Is it supported everywhere without any problem?
Many frameworks use dirname(__FILE__)
to work out the application path based on a known file, usually the index.php
In the Zend Framework, they use the following to define the application path, which is then used everywhere in the app:
define('APPLICATION_PATH', realpath(dirname(__FILE__) . '/../application');