Fortunately, it is very straight forward with GhostJS. The markdown allows you to have HTML markup. Yes that is right you can type anything and it won't be escaped.
So little while ago I created an interactive calculator for kite surfers. So I thought some of you might find it useful.
First: Make sure that you have RequireJS loaded in your page header. You can do that through under Settings -> Code Injection . See image below: