I think there's a distinction to be made between the language spec (e.g., interesting Javascripty details like what is the result of `"" + 1`) and integration i

I think there's a distinction to be made between the language spec (e.g., interesting Javascripty details like what is the result of `"" + 1`) and integration issues like what to do when the browser window detaches, how many threads the browser will devote to running Javascript, what to do when some of those threads appear to be blocked, or how should the runtime/VM attempt to recover from deadlock or OOM.