Not sure why bug 101276 never had its fix checked in, but this isn't behaving like that one. This one is chewing up a lot more memory and CPU. I _do_ get the "A script on this page may be busy, or it may have stopped responding" prompt, but it does NOT let me kill the script! Memory use goes back down to reasonable levels every time that prompt comes us. It seems to be creating recursive iframes, but only one or two per busy prompt. If they were being created due to the while loop I'd have expected a lot more. I don't see a crash. Maybe with less memory you'd trip over one of our many out-of-memory crashes
Created attachment 414035 [details] proof of concept
FYI, this is a major issue with e10s on at the very least all desktop platforms. Every 15 seconds this chews up 1GB of RAM, and closing the tab doesn't stop it. If somebody lands on a page with this and e10s they'll be crashing every time.