Sve je to isto samo je razlika u programskom jeziku koji se koristi. BTW, sve su to server-side skripte jer se izvrsavaju na serveru a ne na korisnickom racunaru (kao JS na primer). Ti si verovatno mislio na SSI - Server Side Include stranice.
Citat:
(Server-Side Includes) - Scripting commands which can be embedded within a web page and parsed by the web server. These are commonly used to include files (such as a header or footer) that are used on multiple pages; show date and time; provide a 'back' link; or execute CGI scripts such as counters and rotating banners.