Some features:

- Very easy to configure and integrate into any existing HTML or PHP page on your website.
- Support many instances
- AJAX check if captcha is currect without refresh page
- Refresh captcha without reaload page
- Verifiying form element is too simple
- Work perfect with Bootstrap 3
- You can easily change the style of captcha
- Less code and easier integration
- Options for randomly and/or manually colors for background, lines and digits/or letters
- TTF fonts

Online Documentation :
http://envato.zooinvest.com/envato/documentation

Bootstrap Demo Login form :
http://envato.zooinvest.com/envato/

Bootstrap Demo Registration form :
http://envato.zooinvest.com/envato/reg-form.html

Default Demo :
http://envato.zooinvest.com/envato/default.html

codecanyon-7265590-simple-jquery-ajax-php-captcha.zip