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Lesson 17 - Guestbook in PHP - continuation

In the previous lesson, Putting PHP interfaces into practice - GuestBook, we started with working on a guestbook with a modular captcha using interfaces. Today, we are going to finish up with this short project.

Printing the form

The next public method for our guestbook will be the renderForm() method. Here's what it will look like:

public function renderForm()
        $name = (isset($_POST['name']) ? $_POST['name'] : '');
        $message = (isset($_POST['message']) ? $_POST['message'] : '');

        echo('<form method="post"><table>');
                echo('<td><input type="text" name="name" value="' . htmlspecialchars($name) . '" /></td></tr>');
                echo('<td><textarea name="message">' . htmlspecialchars($message) . '</textarea></td></tr>');
                echo('<tr><td colspan="2">');
                echo('</td></tr></table><input type="submit" />');

If the user enters an invalid anti-spam verification, we'll use the data that was to be sent to pre-fill the form again and ask the user to enter the anti-spam verification correctly.

The first two lines in the method determine whether


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In this lesson, we're going to finish our PHP guestbook and change it's captcha implementation to image-based responses using our modular interface.

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Article has been written for you by David Capka
The author is a programmer, who likes web technologies and being the lead/chief article writer at He shares his knowledge with the community and is always looking to improve. He believes that anyone can do what they set their mind to.
Unicorn university The author learned IT at the Unicorn University - a prestigious college providing education on IT and economics.
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