Interactive comment section made with pure javascript

I decided to make this with just pure javascript, which I can only assume is terribly inefficient. At this current state it's in dire need of some refactoring and implementing some greater use if DRY principles (For an example comments and replies use almost identical functions which are pretty lengthy). My main goal was really just to get it to work and look good, which I believe i succeeded in.

I'm guessing something like React would have been perfectly suited for an app like this?

Thanks for taking a look!