On 13 Feb 2012, at 06:28, Rui Hu wrote: > How PHP sets variables in $_SERVER, say, $DOCUMENT_ROOT? What should I know > if I want to modify $_SERVER myself? Once your script starts the superglobals are no different to any other variables, except that they're in scope at all times. The only thing you need to bear in mind if you're going to modify them is that other code that's using them will also see your changes, so beware of knock-on effects. -Stuart -- Stuart Dallas 3ft9 Ltd http://3ft9.com/