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![Subject: Web Design and Programming Lecturer: Ahmed Ali Saihood
1
Chapter 5
Part IV
PHP
PHP Global Variables - Superglobals
Several predefined variables in PHP are "superglobals", which means that they are
always accessible, regardless of scope - and you can access them from any
function, class or file without having to do anything special.
PHP $GLOBALS
$GLOBALS is a PHP super global variable which is used to access global variables
from anywhere in the PHP script (also from within functions or methods).
PHP stores all global variables in an array called $GLOBALS[index]. The index holds
the name of the variable.
The example below shows how to use the super global variable $GLOBALS:
<?php
$x = 75;
$y = 25;
function addition() {
$GLOBALS['z'] = $GLOBALS['x'] + $GLOBALS['y'];
}
addition();
echo $z;
?>](https://image.slidesharecdn.com/lecture12-160514114540/75/PHP-Part4-1-2048.jpg)
![Subject: Web Design and Programming Lecturer: Ahmed Ali Saihood
3
<html>
<body>
Welcome <?php echo $_POST["name"]; ?><br>
Your email address is: <?php echo $_POST["email"]; ?>
</body>
</html>
The same result could also be achieved using the HTTP GET method:
<html>
<body>
<form action="welcome_get.php" method="get">
Name: <input type="text" name="name"><br>
E-mail: <input type="text" name="email"><br>
<input type="submit">
</form>
</body>
</html>
and "welcome_get.php" looks like this:
<html>
<body>
Welcome <?php echo $_GET["name"]; ?><br>
Your email address is: <?php echo $_GET["email"]; ?>](https://image.slidesharecdn.com/lecture12-160514114540/75/PHP-Part4-3-2048.jpg)
![Subject: Web Design and Programming Lecturer: Ahmed Ali Saihood
5
PHP $_SERVER
$_SERVER is a PHP super global variable which holds information about headers, paths, and
script locations.
The example below shows how to use some of the elements in $_SERVER:
<?php
echo $_SERVER['PHP_SELF'];
echo "<br>";
echo $_SERVER['SERVER_NAME'];
echo "<br>";
?>
Element/Code Description
$_SERVER['PHP_SELF'] Returns the filename of the currently executing script
$_SERVER['SERVER_NAME']
Returns the name of the host server (such as
www.w3schools.com)
$_SERVER['REQUEST_METHOD']
Returns the request method used to access the page
(such as POST)](https://image.slidesharecdn.com/lecture12-160514114540/75/PHP-Part4-5-2048.jpg)
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PHP-Part4
- 1. Subject: Web Designand Programming Lecturer: Ahmed Ali Saihood 1 Chapter 5 Part IV PHP PHP Global Variables - Superglobals Several predefined variables in PHP are "superglobals", which means that they are always accessible, regardless of scope - and you can access them from any function, class or file without having to do anything special. PHP $GLOBALS $GLOBALS is a PHP super global variable which is used to access global variables from anywhere in the PHP script (also from within functions or methods). PHP stores all global variables in an array called $GLOBALS[index]. The index holds the name of the variable. The example below shows how to use the super global variable $GLOBALS: <?php $x = 75; $y = 25; function addition() { $GLOBALS['z'] = $GLOBALS['x'] + $GLOBALS['y']; } addition(); echo $z; ?>
- 2. Subject: Web Designand Programming Lecturer: Ahmed Ali Saihood 2 In the example above, since z is a variable present within the $GLOBALS array, it is also accessible from outside the function! PHP Form Handling The PHP superglobals $_GET and $_POST are used to collect form-data. The example below displays a simple HTML form with two input fields and a submit button: <html> <body> <form action="welcome.php" method="post"> Name: <input type="text" name="name"><br> E-mail: <input type="text" name="email"><br> <input type="submit"> </form> </body> </html> When the user fills out the form above and clicks the submit button, the form data is sent for processing to a PHP file named "welcome.php". The form data is sent with the HTTP POST method. To display the submitted data you could simply echo all the variables. The "welcome.php" looks like this:
- 3. Subject: Web Designand Programming Lecturer: Ahmed Ali Saihood 3 <html> <body> Welcome <?php echo $_POST["name"]; ?><br> Your email address is: <?php echo $_POST["email"]; ?> </body> </html> The same result could also be achieved using the HTTP GET method: <html> <body> <form action="welcome_get.php" method="get"> Name: <input type="text" name="name"><br> E-mail: <input type="text" name="email"><br> <input type="submit"> </form> </body> </html> and "welcome_get.php" looks like this: <html> <body> Welcome <?php echo $_GET["name"]; ?><br> Your email address is: <?php echo $_GET["email"]; ?>
- 4. Subject: Web Designand Programming Lecturer: Ahmed Ali Saihood 4 </body> </html> GET vs. POST Both GET and POST create an array (e.g. array( key => value, key2 => value2, key3 => value3, ...)). This array holds key/value pairs, where keys are the names of the form controls and values are the input data from the user. Both GET and POST are treated as $_GET and $_POST. These are superglobals, which means that they are always accessible, regardless of scope - and you can access them from any function, class or file without having to do anything special. $_GET is an array of variables passed to the current script via the URL parameters. $_POST is an array of variables passed to the current script via the HTTP POST method. When to use GET? Information sent from a form with the GET method is visible to everyone (all variable names and values are displayed in the URL). GET also has limits on the amount of information to send. The limitation is about 2000 characters. However, because the variables are displayed in the URL, it is possible to bookmark the page. This can be useful in some cases. GET may be used for sending non-sensitive data. When to use POST? Information sent from a form with the POST method is invisible to others (all names/values are embedded within the body of the HTTP request) and has no limits on the amount of information to send.
- 5. Subject: Web Designand Programming Lecturer: Ahmed Ali Saihood 5 PHP $_SERVER $_SERVER is a PHP super global variable which holds information about headers, paths, and script locations. The example below shows how to use some of the elements in $_SERVER: <?php echo $_SERVER['PHP_SELF']; echo "<br>"; echo $_SERVER['SERVER_NAME']; echo "<br>"; ?> Element/Code Description $_SERVER['PHP_SELF'] Returns the filename of the currently executing script $_SERVER['SERVER_NAME'] Returns the name of the host server (such as www.w3schools.com) $_SERVER['REQUEST_METHOD'] Returns the request method used to access the page (such as POST)