Take an existing form and add functionality to it with JavaScript. It provides error messages based on the user input, and other interactivity with selects & checkboxes.
Site is published at https://apalm112.github.io/FSJS-Interactive-Form/
Source for help with implementing the strike-through feature: https://stackoverflow.com/questions/30975459/add-strikethrough-to-checked-checkboxhttp://www.bootply.com/X5cUPLtbyP#http://regexr.com/