I'm confused. Are you having trouble putting the controller together or is it working now?
If you're having trouble, some places to check are the element IDs. Also, the code is run at startup (on scene load). It's using event listeners, which is JavaScript code that is outside of Hype's JavaScript API – but it is standard JavaScript.
Honestly, I forgot what I built. I went back to look at the code and I couldn't remember what I was trying to do. It took me a while to remember. I was really in the zone. It's good that I wrote this stuff down. HA HA.