Oops!
I'm not sure whether i can explain it correctly. I will try my best.
As
$tmp_thispath refers to /starcom/index.php, when i use the function
dirname it refers to /starcom folder.
Basically,
(dirname($tmp_thispath) == '/') just refers to my URL being
http://www.example.com/starcomFor,
(dirname($tmp_thispath) == '/')?'./logon':'../logon'; It means, If directory of
$tmp_thispath is equal to
http://www.example.com/starcom.
The page will be directed to the current directory as shown
./logon and the URL will be
http://www.example.com/starcom/logonelse
The page will be directed to the previous directory path as shown
../logon. For example, my URL is currently
http://www.example.com/starcom/anything/. It will direct it to
http://www.example.com/starcom/logon.
The differences between ./ and ../ is just referring to current or previous directory path.
I hope that i have explained it clearly and understandable.
I'm sorry that i did not state down how i manage to get it at that time, as i was too busy with changing my codes and stuff.
Cheers,

/Nikas