PHP Super Global Variables

There are various predefine “superglobals” in PHP. These variables can easily accessible in function or class. Following are the superglobals variables:

• $GLOBALS
• $_SERVER
• $_REQUEST
• $_POST
• $_GETetc.

PHP $GLOBALS The “$GLOBAL” isa keyword that is used to accesssuper global variablefrom anywhere in the PHP script. Example 1:

<?php
$nos1 = 20;
$nos2 = 30;
function addition() {
    $GLOBALS['nos'] = $GLOBALS['nos1'] + $GLOBALS['nos2'];
}
addition();
echo $nos;
?>

Output 50 PHP $_SERVER PHP  $_SERVER is a PHP super global variable that holds the information about headers, paths, and script locations. Example 2:

<?php
echo $_SERVER['PHP_SELF'];
echo "<br>";
echo $_SERVER['SERVER_NAME'];
echo "<br>";
echo $_SERVER['HTTP_HOST'];
echo "<br>";
echo $_SERVER['HTTP_USER_AGENT'];
echo "<br>";
echo $_SERVER['SCRIPT_NAME'];
?>

Output /crud/hello.php localhost localhost Mozilla/5.0 (Windows NT 6.3; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.84 Safari/537.36 /crud/hello.php Superglobals variables are given below:

Element/Code	Description
$_SERVER['PHP_SELF']	Returns the filename of the currently executing script
$_SERVER['GATEWAY_INTERFACE']	Returns the version of the Common Gateway Interface (CGI) the server is using
_SERVER['SERVER_ADDR']	Returns the IP address of the host server
$_SERVER['HTTPS']	Is the script queried through a secure HTTP protocol
$_SERVER['SCRIPT_URI']	Returns the URI of the current page

PHP $_REQUEST PHP $_REQUEST is used to gather data after submitting html form. Example:

<html>
<body>
<h3>Enter Your Name to Display result</h3>
<form method="post" action="<?php echo $_SERVER['PHP_SELF'];?>">
<input type="text" name="fname" placeholder="Enter your name..."><br><br>
<input type="submit">
</form>
<?php
if ($_SERVER["REQUEST_METHOD"] == "POST") {
    // collect value of input field
    $name = $_REQUEST['fname'];
if (empty($name)) {
echo "Name is empty";
    } else {
echo $name;
    }
}
?>
</body>
</html>

PHP $_POST PHP $_POST is used to collect data after submitting the form using“$_post”method. It is also used to pass the variables. Example

<html>
<body>
<h3>Enter Your Name to Display result</h3>
<form method="post" action="<?php echo $_SERVER['PHP_SELF'];?>">
<input type="text" name="fname" placeholder="Enter your name..."><br><br>
<input type="submit">
</form>
<?php
if ($_SERVER["REQUEST_METHOD"] == "POST") {
    // collect value of input field
    $name = $_POST['fname'];
if (empty($name)) {
echo "Name is empty";
    } else {
echo $name;
    }
}
?>
</body>
</html>