<h1>MathGuard form antispam protection</h1>
<p>Creating this website I attracted lots of spambots to flood my forum, my programming resources, freelance database and other forms, but you probably know this situation very well. So I decided to create a simple PHP Class which could help me and probably other people to deal with the spam.</p><p> </p><p><img src="http://www.codegravity.com/img/mathguard01.gif" border="1" alt="" /></p><p> </p>
<p>You have probably seen this solution before on some other websites, it's nothing new, but I did it by myself and the way I wanted and I am using it everywhere it's needed.</p><p> </p> <h2>The principle of this antispam class </h2> <p>The principle is very simple - The class inserts a small piece of HTML code into your form - an expression consisting of two random numbers, one text input field for user's answer, and one hidden field with the hashcode.</p><p>When user submits the form with the answer, the answer is being hashed and compared to the security code that has been submitted as well.</p><p> </p><h2> How to set up this PHP antispam class and use it on your website?</h2><h3><strong><u>1. Download the code of MathGuard</u></strong></h3><p>Go to the <a href="http://www.codegravity.com/download/">download section</a> on this website and find there the <strong>mathguard.zip</strong> </p><p>2. Unzip the archive and copy the </p><h3><u><strong>3. Open the code with the form you want to protect</strong></u></h3><p> </p><h3><u><strong>4. Add the following code snippet (the one in the ellipse)</strong></u></h3> <img src="http://www.codegravity.com/img/mathguard02.gif" border="1" alt="" /><br /><br /><h3><u><strong>5. Protect the form handler</strong></u></h3><p> <img src="http://www.codegravity.com/img/mathguard03.gif" border="1" alt="" /></p> <pre> /* first we need to require our MathGuard class */<br /> require ("ClassMathGuard.php");<br /> /* this condition checks the user input. Don't change the condition, just the body within the curly braces */<br /> if (MathGuard :: checkResult($_REQUEST['mathguard_answer'], $_REQUEST['mathguard_code'])) {<br /> echo ("Great !"); //insert your code that will be executed when user enters the correct answer<br /> } else {<br /> echo ("Bad answer, go back to school !"); //insert your code which tells the user he is spamming your website<br /> }<br /></pre><h3><u><strong>6. Open the form in your browser and you should see the mathguard's security question there</strong></u> </h3><h1> </h1><h3><u><strong>7. Example</strong></u></h3><p><br /> There is also an example in the mathguard.zip. It features a simple form and one simple form handler which displays the data.</p><p> </p><h3><u><strong>8. Enjoy !</strong></u> </h3><p> If you'd have any questions, feel free to write to the comments or directly to my email<br /> </p><p>
<a href='http://www.CodeGravity.com'>CodeGravity.com</a>
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