One of the most powerful features of PHP is the way it handles HTML forms. The basic concept that is important to understand is that any form element will automatically be available to your PHP scripts. Please read the manual section on Variables from external sources for more information and examples on using forms with PHP. Here is an example HTML form:
Example #1 A simple HTML form
<form action="action.php" method="post"> <p>Your name: <input type="text" name="name" /></p> <p>Your age: <input type="text" name="age" /></p> <p><input type="submit" /></p> </form>
There is nothing special about this form. It is a straight HTML form with no special tags of any kind. When the user fills in this form and hits the submit button, the action.php page is called. In this file you would write something like this:
Example #2 Printing data from our form
Hi <?php echo htmlspecialchars($_POST['name']); ?>.
You are <?php echo (int)$_POST['age']; ?> years old.
A sample output of this script may be:
Hi Joe. You are 22 years old.
Apart from the htmlspecialchars() and
(int) parts, it should be obvious what this does.
htmlspecialchars() makes sure any characters that are
special in html are properly encoded so people can't inject HTML tags
number, we can just convert
it to an integer which will automatically get rid of any
stray characters. You can also have PHP do this for you automatically by
using the filter extension.
The $_POST['name'] and $_POST['age']
variables are automatically set for you by PHP. Earlier we
used the $_SERVER superglobal; above we just
introduced the $_POST
superglobal which contains all POST data. Notice how the
method of our form is POST. If we used the
method GET then our form information would live in
the $_GET superglobal instead.
You may also use the $_REQUEST
superglobal, if you do not care about the source of your request data. It
contains the merged information of GET, POST and COOKIE data.
You can also deal with XForms input in PHP, although you will find yourself comfortable with the well supported HTML forms for quite some time. While working with XForms is not for beginners, you might be interested in them. We also have a short introduction to handling data received from XForms in our features section.