Way to output HTML on professional websites

Hi guys Just a little question: I've programmed some nice little websites up to 25'000 lines of code. Now if I see some bigger websites just as facebook and so on, how are they printing their website out? Does it work like <?php echo "<html><head>..."; ?> or do they output it like <?php if (true) { ?> <body> </body> <?php } else { ?> <head> </head> <?php } ?> Or is the code even generated or gotten from a database and evaluated? How does the website itself gets printet on really professional websites? Thanks for answer! Flo ========================== Florian Müller floripipo@hotmail.com==========================