PHP Form
Free PHP forms, scripts, resources and tutorials.


Captcha Protection

Published: 03/03/10


Creating a CAPTCHA with PHP :: PHP Tutorial

- Requirement(s): PHP Server

Creating a CAPTCHA with PHP :: PHP Tutorial

This tutorial will show you how to create a form with Captcha. 1.Sessions in PHP are started by using the session_start() function. Like the setcookie( ) function, the session_start( ) function must come before any HTML, including blank lines, on the page.
Code:
<?php session_start(); ?>
2.Imagecreate - Create a new palette based image.
Code:
$img = imagecreate(40, 20); 
3.The function imagecolorallocate creates a color using RGB (red,green,blue) format.
Code:
$black = imagecolorallocate($img, 0, 0, 0);
4.Displaying the random text on the captcha image
Code:
$numero = rand(100, 999);
5.Check if the security code and the session value are not blank and if the input text matches the stored text.
Code:
if(($_POST['check']) == $_SESSION['check']) 
{ echo 'Input OK';
}else{ 
echo 'Input Wrong';        
}

Files


index.php:
Code:
<form method="POST" action="cc.php"> 
<img src="captchas.php"> <br>
<input type="text" size="10" name="check"> <br> 
<input type="submit" name="submit" value="submit"> 
</form>
captchas.php:
Code:
<?php 
session_start(); 
//imagecreate -- Create a new palette based image
$img = imagecreate(40, 20);
//displaying the random text on the captcha image
$black = imagecolorallocate($img, 0, 0, 0); 
$numero = rand(100, 999);
$number = $black . $numero;
$_SESSION['check'] = ($numero); 

$white = imagecolorallocate($img, 255, 255, 255); 
imagestring($img, 10, 8, 3, $numero, $white); 
header ("Content-type: image/png"); 
imagepng($img); 
?>
cc.php:
Code:
<?php 
//Sessions in PHP are started by using the 
//session_start() function.  
//Like the setcookie( ) function, 
//the session_start function must come before any HTML, 
//including blank lines, on the page.session_start(); 
//Check if the security code and 
//the session value are not blank 
//and if the input text matches the stored text
if(($_POST['check']) == $_SESSION['check']) { 
echo 'Input OK';
}else{ 
echo 'Input Wrong';        
}

example 2

Comments


Add a Comment

Name:


Comment:




Sitemap