JPGs are much better quality than GIFs, but also take up much more memory. Hex Short for hexadecimal. Hex is a base 16 number system. For more information, see the hexadecimal part of the tutorial. Script Scripts are programs your HTML page can tell the server to run.
Scripts can do just about anything, from processing information to generating fractals.
The advantage of Perl is it's simplicity and how well it interacts with HTML browsers. Because of this, Perl is the chosen language for writing scripts. ISP Internet Service Provider. This is the place you call when you want to get online. POP 1 Point of Presence.