Note: This is a 'superglobal', or
automatic global, variable. This simply means that it is available in
all scopes throughout a script. There is no need to do
global $variable; to access it within functions or methods.
Note:
The variables in $_REQUEST are provided to the
script via the GET, POST, and COOKIE input mechanisms and
therefore could be modified by the remote user and cannot be
trusted. The presence and order of variables listed in this array
is defined according to the
PHP variables_order
configuration directive.