At a technical level, JSFiddle or equivalent comes kind-of close. Set up a template with a nice big <canvas> element, then you've got a simple imperative API to draw stuff which really does come pretty close to what you'd get from a BASIC> prompt.
That said, I wonder if it's even possible to replicate the C64 (or equivalent) experience. Looking back, I think a big part of the "magic" was that there were relatively few distractions. Just you, the machine, and (maybe) some paper documentation or a magazine with a few listings [1]. Can that be replicated once you're used to network-connected computers that are gateways to almost unlimited amounts of video, colourful games, etc.?
(My child is getting to the point where I wish I knew the answers to some of this myself...)
[1] I'm pretty certain type-in listings were the biggest contributor to my learning, early on. That doesn't seem to be something that comes up terribly often nowadays (although I note that Zed Shaw's "Learn Python the Hard Way" is pretty specific about telling you to hand-type in the examples...)
In my opinion anything js-related is the furthest you can get from "power on to BASIC". I can say that for me it feels less enjoyable to have to rely on an external website (like jsfiddle), also requiring that you be able to write (very) basic HTML and maybe even CSS. I agree that once it's set up it can be very interactive, but it's non-trivial to get to that point
That said, I wonder if it's even possible to replicate the C64 (or equivalent) experience. Looking back, I think a big part of the "magic" was that there were relatively few distractions. Just you, the machine, and (maybe) some paper documentation or a magazine with a few listings [1]. Can that be replicated once you're used to network-connected computers that are gateways to almost unlimited amounts of video, colourful games, etc.?
(My child is getting to the point where I wish I knew the answers to some of this myself...)
[1] I'm pretty certain type-in listings were the biggest contributor to my learning, early on. That doesn't seem to be something that comes up terribly often nowadays (although I note that Zed Shaw's "Learn Python the Hard Way" is pretty specific about telling you to hand-type in the examples...)