I'm so relieved to hear all the redundancy and testing in place. I had heard that the touchscreens were built in Chromium/JS and was rather alarmed. Don't get me wrong – I do a lot of web stuff and I love that environment, but I've never seen a web app I would trust two human lives to. This, however, sounds like they really thought it through and made it safe.
A contrary opinion - a tool/framework used and tested by billions of people every day is a lot less prone to crashing when used for its intended purpose than something custom-built. There are tons of developers out there building complex apps by following beginner JavaScript tutorials, but SpaceX is obviously going to enforce better standards. HTML/CSS/JavaScript/V8 are all extremely solid technologies that have stood the test of time, and there is nothing better to build a user interface with today.
