> As it stands right now a while(true) loop crashes the page

> [...] I also desperately want to prevent crashing as a result of logic errors

I could be wrong here, but I think the new Site Isolation stuff in Chromium[0] may mean that you can sandbox an iframe to a different origin, so that the main threads of the top frame and the iframe aren't synced. So the iframe where the code is running would freeze, but the main frame would still be responsive. Again, I may have misinterpreted this because I only read about it in passing, and it was a while ago.

[0] https://www.chromium.org/Home/chromium-security/site-isolati...