View source for Web forms and PHP

This article discusses [[Form (HTML)|web forms]] and [[PHP]].

== Example ==

The examples below are based on [http://php.net/manual/en/tutorial.forms.php this page @ php.net].

The examples show excerpts, not the complete HTML.

The actual pages should contain complete and valid HTML.  

=== Create web form ===

Create an HTML page (call it <code>formpage.html</code>, for convenience) containing this web form:

<pre>
<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>
</pre>

Note that the form's action attribute is set to <code>action.php</code>.  When the user submits the form, the form data will be sent to a [[PHP]] page named <code>action.php</code> (in the same folder as the web form page).  The file name <code>action.php</code> is arbitrary -- any valid file name will work.

The form contains two text input fields, named <code>name</code> and <code>age</code>.

In a form element, the action attribute specifies where the data will be sent when the user submits the form.  In this example, the data will be sent to a PHP page named <code>action.php</code>.

Also note that the form element has the method attribute set to <code>post</code>.  (There are two widely used methods:  <code>post</code> and <code>get</code>.

=== Create PHP to display submitted data ===

The <code>action.php</code> page contains the following code (note that the code has both HTML and PHP):

<pre>
Hi <?php echo htmlspecialchars($_POST['name']); ?>.
You are <?php echo (int)$_POST['age']; ?> years old.
</pre>

There are two PHP code islands (blocks of PHP code), mixed with HTML.

Both code islands use the <code>echo</code> statement to generate ("echo") text which will be sent to the user:

The first code island looks like this:

<pre>
<?php echo htmlspecialchars($_POST['name']); ?>
</pre>

This PHP code refers to the data received from the web form input named "name":

<code>$_POST['name']</code>

The PHP function <code>htmlspecialchars()</code> converts "special characters" (preventing user from submitting HTML, which could be a security risk).

The second PHP code island looks like this:

<pre>
<?php echo (int)$_POST['age']; ?>
</pre>

The <code>(int)</code> indicates an integer (numeric value).

This PHP code refers to the data received from the web form input named "age":

<code>$_POST['age']</code>

=== Results ===

When the user fills out and the submits the web form, the <code>action.php</code> page will display something like this:

<pre>
Hi Joe. You are 22 years old.
</pre>

=== Matching web form inputs with PHP ===

It is critical to match up the name of the web form inputs ("name", "age") with the <code>$_POST[]</code> references (<code>$_POST['name']</code>, <code>$_POST['age']</code>).

Similarly, if your web form has an input named "favorite_color", your PHP page should say <code>$_POST['favorite_color']</code>.

Do not use spaces in the names of your inputs.

=== Complete web form page ===

The complete web form page might look something like this:

<pre>
<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8"/>	
		<title>Web forms and PHP</title>
	</head>
	<body>
		<h1>Web forms and PHP</h1>
		<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>
	</body>
</html>
</pre>

=== Complete PHP page ===

The complete PHP page might look something like this:

<pre>
<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8"/>	
		<title>Web forms and PHP</title>
	</head>
	<body>
		<h1>Display submitted data</h1>
		Hi <?php echo htmlspecialchars($_POST['name']); ?>.
		You are <?php echo (int)$_POST['age']; ?> years old.
	</body>
</html>
</pre>

== See also ==

* [[Form (HTML element)]]

== External links ==

* [http://php.net/manual/en/tutorial.forms.php Dealing with Forms]


[[Category:PHP]]
[[Category:Web design and development]]