I got the Radar demo working in HTML5, finally. In order to do it, absent a better debugging methodology, I created a new project and meticulously re-built the demo line by line. I’m still not entirely sure why this works while the first one doesn’t — I still need to look at it more closely.
The resulting project isn’t feature-complete yet, but the only missing feature is color coding for IFF, and isn’t where the problem was. Once I’ve finished adding that feature, I’ll update the source download.
For now, here’s an in browser preview of what the radar demo looks like in action: