Captcha PHP

The captcha.php module prevents WWW bots from submitting HTML forms by presenting an image that must be identified before the submission will be accepted. It is very easy to use and integrate because of its simple API and sensible defaults. Built-in timeouts make database tracking unnecessary, and by using data: URIs it does not need any temporary files. For visually impaired users or text-only browsers, a letter riddle can be provided instead of an image.