Description:

1. First, you need to copy the code sample provided and save it as a php file.
2. Next, create a background and a cover image or image. The background can be some kind of simple texture, not too dark though. Cover image can be lines. Play around with it to get the effect you want. In the code sample, replace the links to the correct paths to the images you created.
3. On the form you would like to protect from spam prevention, you need to insert the script as an image. That code woud look something like this:
   
   <img src="http://www.yoursite.com/path/to/CAPTCHA.php">
   
   
4. Next, create an html text box (within a form) for the user to enter the CaSe sEnSiTiVe code that appears from the image/script. That code would look something like this:
   
   Enter Code: <input type="text" id="verify" name="verify" value="">
   
   
5. Then in the validation part of your form, you need to ensure that the text box is not blank, and then if the values entered in the text box are equal to the code generated. The code generated will be stored in $_SESSION['code']; you can change that to whatever you want. Here is an example code to do that:
   
   if(!$_POST['verify']) {
       die('Verify field was blank.');
           } else {
   if($_SESSION['code'] != $_POST['verify']) {
       die('You did not enter the code from the box correctly.');
   }