http://www.abc.com/example/index.php/check/issue[
^]
If we run, $_SERVER['PHP_SELF'], it will result as '/example/index.php/check/issue';
If we run, $_SERVER['SCRIPT_NAME'], it will result as '/example/index.php';
If we run, $_SERVER['DOCUMENT_ROOT'], it will result the document root directory under which the current script is executing, as defined in the server's configuration file. For example, E:/projects/abc/example.
But, no idea about $_SERVER['ORIG_SCRIPT_NAME'] and to be honest, heard the word 'ORIG_SCRIPT_NAME' first time :).
Hope this one will help you :).