I've watched a couple of these 'casts now and they're really quite informative, although I do wonder if the author constantly adding/editing comments as the mai

I've watched a couple of these 'casts now and they're really quite informative, although I do wonder if the author constantly adding/editing comments as the main narrative/exposition method is the most instructive. Obviously there will be things that should be commented for explanation, but it feels like it should be for more 'stable' (I'm struggling for the right term here) notes. In contrast to a traditional presentation where you have slides + narration (which later becomes a transcript), the 2 forms of information are merged here, which muddies things a bit. Keeping it all-text is essential; the 15x multiplier is great, and utterly impractical if you're also trying to follow a voice-over, but maybe it should be in another window, perhaps with some sort of temporal glow-highlight or visual-diff style emphasis on what's being changed, to draw those things apart. That's all a bit cssdeck-meta though. On this demo specifically, I'm curious why part of the behaviour was tied to the role="" attribute, and part was done with classes. Can anyone with more frontend experience than me (so, essentially everyone) suggest where you might choose one approach "foo[attr=val]" over ".foo .bar"?