Hello BigEd,
Your post really caught my eye, not because of the in-browser 6502 assembler/simulator, but it's use in an educational context. The goal of a new program I've been working on has the goal of being used in an educational context, and I'd personally like to know the viability of that goal. Not sure if you are of a similar generation of me, I grew up in the 80s and 90s, and Maxis "Software Toys" as they were called at the time were everywhere in the schools. This is where I got the initial idea for my simulator, a fun 6502 computer science software toy that students and hobbyist can enjoy alike. It is currently pretty far along with my next big planned feature being an EGA compatible text framebuffer with the standard size of 80x25 which is fully memory mapped, much like the console provided in this web-based simulator. It is an exact copy of the EGA one as well, and my current implementation supports loading a video memory dump taken from say a DosBox session and I was able to seamlessly load it into my framebuffer, so I think I got it.
I have a huge passion for programming ans computer science and I'd really love to find a way into the educational market to bring this passion to many more. I highly recommend checking out the website I put together earlier this year, along with a recent post I made on the subject on this forum for some additional info, as I don't want to rewrite everything here.
http://www.hackers-edge.com/
Oh, if you scroll to the bottom of each page I have there, there is a YouTube video you can watch with a full demonstration of it being used, there is a download as well, so you can also give it a shot yourself of course too.
