Captchas are still the standard to verify that the user performing an action (like filling forms) is a real human but not a bot.
PlayThru is a free and different alternative to other standard captcha solutions by asking users to play a very short game rather than guessing the scrambled letters (which is also like a game but “so” less fun).
The games are simply drag ‘n’ dropping items to the right places depending on the questions asked.
No Flash is used, all HTML5 and they work on mobile as well. Also, there are plugins for popular apps (like WordPress, phpBB) and libraries for various scripting languages).
PlayThru is free for unlimited use and paid plans exist for anyone that need more features and customization options.
Requirements: No Requirements
NuCaptcha is a free captcha service that uses motion video to authenticate human web interactions.
Compared to image-based captchas, it is a harder-to-recognize solution for bots and can be read easier by humans which is great.
With the help of an API, NuCaptcha can be implemented into any website (sample codes provided) and there is also a WordPress plugin offered.
The captchas can be customized in means of skin, background and message displayed which helps a better visual integration with the websites.
LOG.ME.IN is a free PHP user management script for easily protecting site content and displaying it to only registered users.
It is also an instant solution for creating the common membership modules like sign-up, login or "forgot password".
The script uses MySQL as the database and has a web-based installer for a quick installation.
LOG.ME.IN has a strong focus on security: it is integrated with reCAPTCHA, performs a safe session handling and SQL injection/XSS proof.
And, it has a back-end to manage users (listing, editing and deleting them).
Requirements: PHP 5+, MySQL 4.1+
Tutorialzine is sharing a nice tutorial with source on creating a fancy Ajaxed contact form that is built with jQuery & PHP.
It takes advantage of 2 jQuery plugins:
and a PHP class:
The contact form also has a basic captcha which works by asking the sum of 2 random numbers.
To check a demo of the form, click here.
Compatibility: All Major Browsers