[pavlov]

If that language feature had been included, the early web would have been filled with tutorials that say: “Don’t forget to wrap all your code in lockUI{} because that guarantees it runs correctly and things don’t suddenly change behind your back!”

And then we’d have the popular web frameworks just taking the lock and running all user code inside it, and everything would be the same as today.

[greggyb]

But we’d have options. ~There aren’t any today.~

Ninja edit: there haven’t been any until workers.