PHP Superglobals are predefined global variables that are found within the PHP library. They can be accessed at any point of the program.
PHP Superglobals :
PHP superglobals are callable from whatever scope, whether it is within a class, function, or separate file.
There exists a list of PHP superglobals which are basic and commonly used. They are always written in capital letters.
PHP $GLOBALS :
This superglobal variable is used whenever there is the need to access global variables from anywhere within a PHP source script.
PHP reserves the global variables within a single array named $GLOBALS[index], where index represents the name of the specific variable.
<?php
$i = 12;
$j = 46;
function sum() {
$GLOBALS['x'] = $GLOBALS['i'] + $GLOBALS['j'];
}
sum();
echo "Addition : ". $x;
?>Output:
Addition : 58PHP $_SERVER :
This suberglobal variable is used to hold information related to paths, headers, and script locations in PHP.
<?
php echo $_SERVER['HTTP_HOST']."</br>";
echo $_SERVER['SERVER_NAME']."</br>";
echo $_SERVER['SERVER_PORT']."</br>";
?>Output:
localhost
localhost
80The above code extracts information from the server and presents it on the browser, which is represented by port 8080; as below:
There are many other $_SERVER[] superglobals existent in PHP.
They are listed below :
$_SERVER['SERVER_ADDR'] Returns the host server IP address
$_SERVER['PHP_SELF'] Displays the filename of the script being executed.
$_SERVER['SERVER_SOFTWARE'] Displays the server identification string.
These are few examples of the server-related superglobals. Refer to the Reference section for more Server superglobals.
PHP $_REQUEST[]
It is a variable that is used to collect information after the submission of an HTML form.
$_POST[]
It is a superglobal variable used in forms for data collection after submission of HTML forms. It can be used to pass variables. It is used with the method=”post”
$_GET[]
It is commonly used with forms too, through the method=”get”. It can obtain hyperlinks and URLs to certain documents both online and offline.
Examples of the globals above are embedded within the following program:
<html>
<body>
<form method="post" action="<?php echo $_SERVER['PHP_SELF']; ?>">
Name: <input type="text" name="textarea">
<input type="submit">
</form>
<?php
if ($_SERVER["REQUEST_METHOD"] == "POST") {
$name = $_POST['textarea'];
if (empty($name)) {
echo "Please enter name";
} else {
echo $name;
}
}
?>
</body>
</html>Output:
Happy Learning 🙂
