PHP Variables
PHP Data Types
PHP Echo & Print
PHP Strings
PHP Numbers
PHP Constants
PHP Operators
PHP if...else...elseif Statements
Switch Statement
PHP Loops
PHP Arrays
Superglobals
PHP Coding Standards
PHP Form Handling
PHP Form Validation
PHP URLs Validation
PHP Form Required Validation
Complete Form Example
PHP File Functions Open/Read
PHP File Create/Write
PHP File Upload
PHP Cookies Handling
PHP Session Handling
PHP filter_var() Function
PHP Validation Filters
PHP Sanitization Filters
Using Filters
Filters Advanced
JSON
PHP Date and Time
MySQL Database
MySQL Connect
MySQL Commands-Creating a Table
MySQL Commands-Inserting The data
MySQL Commands-Prepared Statement
MySQL Commands-Selecting The Data
MySQL Commands-Where and Order By
MySQL Commands-Deleting And Updating The Data
PHP-OOP Introduction
PHP-Classes/Objects
PHP-Constructor/Destructor
PHP-Access Modifiers
PHP-Inheritance
PHP-Inheritance and Protected Access Modifier
PHP-Overriding Inherited Methods
PHP-Final keyword
PHP-Abstract Classes
PHP-Constants
PHP-Traits
PHP-Static Methods and Properties
Introduction to Functions
Defining A function
Returning Values From A Function
Dynamic Function Calls
Variable Scope
Understanding Arguments Or Parameters
Testing For A Function Existence
Returning Multiple Values From A Function
Making practical Use By Building Code Libraries For Code Re-usability
Using Include() And Require()
Some variables in php are always accessible, and they have a global scope and are predefined. Those variables are known as SuperGlobals. You can access these super globals from any file, class or a function. We have below super globals in php.
$GLOBALS
$_SERVER
$_REQUEST
$_POST
$_GET
$_FILES
$_ENV
$_COOKIE
$_SESSION
Let us discuss few super globals in this section and other we will discuss in the later sections.
>$GLOBALS
$GLOBALS is a superglobal variable that allows us to access global variables whenever and wherever required in the php script. You can even call these global variables from methods or functions. $GLOBALS[] array in php stores all the global variables and the variable name is present under the index of this array.
For example, in the below code, the global variable can be accessed outside the function also.
$a = 25; $b = 5;
function division()
{
$GLOBALS[‘x’] = $GLOBALS[‘a’] / $GLOBALS [‘b’];
}
division();
echo $x;
?>
The output of the above-written code will be 5.
>$_SERVER
$_SERVER is a super global that helps us to store the header, paths and script location information. You can use this super global variable as below to retrieve the information.
echo “ $_SERVER[‘SERVER_NAME’];
echo “
”;
echo “$_SERVER[‘PHP_SELF’];
echo “
”;
echo “$_SERVER[‘HTTP_HOST’];
echo “
”;
echo “$SERVER[‘SCRIPT_NAME’];
echo “
”;
echo “$_SERVER[‘HTTP_USER_AGENT’];
echo “
;
?>
The output will show server name, the file you are currently working on, HTTP hostname, script name and user agent.
>$_REQUEST
$_REQUEST is a super variable that collects the information when you submit an HTML form after you submit the data in a form. Let us see in the below example.
Name:
if ($_SERVER["REQUEST_METHOD"] == "POST") {
// collect the name of file
$name = $_REQUEST['file_name'];
if (empty($name)) {
echo "Name is not entered";
} else {
echo $name;
}
}
?>
When the user enters input and submit the button, data is sent to the file present in the action attribute of the form tag and $_REQUEST super global is used to collect that information from the form.
>$_POST
$_POST is a super global variable that collects the information users submit on a form similar like request method, but while using the Post method for transferring data, the data is not visible in the query string. We can use $_POST super global variable as below.
Name:
if ($_SERVER["REQUEST_METHOD"] == "POST") {
// collect value of input field
$name = $_POST['file_name'];
if (empty($name)) {
echo "Name is not entered";
} else {
echo $name;
}
}
?>
When the user enters input and submit the button, data is sent to the file present in the action attribute of the form tag and $_POST super global is used to collect that information from the form without displaying the query string.
>$GET
$_GET is a super global variable that collects the information users submit on a form similar like Post method but while using get method for transferring data, the data is visible in the query string and values are not hidden. It stores the value that comes in the URL like filename, username, password etc. We can use $_GET super global variable as below.
if( $_GET["username"] || $_GET["age"] )
{
echo "Welcome ". $_GET['username']. "
";
echo "You are ". $_GET['age']. " years old.";
exit();
}
?>
Name:
Age:
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