( string pathname [, int mode [, bool recursive [, resource context]]] )
Attempts to create the directory specified by pathname.
Note that you probably want to specify the mode as an
octal number, which means it should have a leading zero.
The mode is also modified by the current umask, which you
can change using umask().
Mode is ignored on Windows, and became optional in PHP 4.2.0.
The mode is 0777 by default, which means the widest possible
access. For more information on modes, read the details
on the chmod() page.
Example 1. mkdir() example
Returns TRUE on success or FALSE on failure.
As of PHP 5.0.0 mkdir() can also be
used with some URL wrappers. Refer to Appendix M
for a listing of which wrappers support mkdir().
The recursive parameter was added as of PHP 5.0.0.
Note: When safe mode is enabled, PHP checks whether
the directory in which you are about to operate has the same UID (owner) as the
script that is being executed.
See also rmdir().