This is a demo of a UI component I made for Emailchef. Look at its code (an extract) if you are curious:
https://github.com/leoperria/signup-forms/tree/master/web/app/modules/signup_forms
It's based on html5, angularjs, jquery, jqueryUI.
To see it working in production please subscribe free to http://www.emailchef.com/ !
Link to the full video: http://vimeo.com/105247568