> Now, do autocompletes
This is kind of ready, see datalist element.
https://developer.mozilla.org/en-US/docs/Web/HTML/Element/da...
I know about datalist, but it's the saddest autocomplete experience you can offer. If something is not fully styleable, it's automatically garbage. If it's styleable, it may be decent.
Now, I understand why datalist is not styleable the way it is implemented right now. On Android, the suggestions come on the top bar of the native keyboard, so it doesn't make sense to be able to put arbitrary divs there. But in that case, there should be an alternative styleable autocomplete element.
Another element that is unstyleable crap is <input type=file>, <audio> too.