PHP BasicIntroduction to PHP PHP Starting Requirements Downloading XAMPP Local Server PHP Variable Concept and Data Type PHP Coding Syntax Showing Output in PHP PHP String Concatenation Increment & Decrement in PHP PHP Logical Operator and Usage Part-1 PHP Logical Operator and Usage Part-2 PHP Comparison Operators Arithmetic and Assignment Operators PHP Switch Case Statement For loop in PHP Super Global Variable $_REQUEST and $_GET Part-1 String Length in PHP Function Declaration and Usage
In php there eight variables. These eight variables are fixed, constant and can't be changed. This variable is started with $_. For several reasons, they are known as super global variables. Different variables have different duty to do. Some works with file, some works with request and some works to send data to sever. Let’s see the below table for better clearance.
|$_FILES||Works with File(Upload, Check Type)|
|$_POST||Sends Data to Server|
|$_REQUEST||Responds to The Request|
|$_SESSION||Set Session for User Access|
|$_COOKIE||Set Cookie for User Identification|
|$_SERVER||Request Server and Get Server Info|
$_ENV is used not so much but has usage also.