PHP contains so many predefined global variables which is called as super globals. These variables are started with an underscore (_) symbol, for example, $_GET, $_POST and etc. Unlike, user defined global variables, this kind of super globals can be accessed from PHP function without using global keyword or anything.
Super globals used to contain array of information about form contents, sessions, cookies and also have some environment information, which is called as EGPCS information in short. The expansion of this acronym is shown in the below list.
While executing the PHP program, the global array data are loaded in the order specified using variables_order directive of the PHP configuration file php.ini, and we can control this order and can decide about which of these variable is required to be displayed. To get the elements of $_GET, $_POST and $_COOKIE as a whole into an single associative array, we can use another PHP global variable named $_REQUEST.
This PHP code tutorial was published on May 3, 2013.