Ctrl-W closes the browser with no warning

[mattgodbolt]

Ideally we'd trap ctrl-W but that seems impossible. However, it's a fairly common thing to press when playing Exile, and it's disastrous: closing the browser!

Closing the browser with a game running should at least prompt an "Are you sure?" though it's going to be tricky to come up with non-annoying behaviour. Maybe only ask if there's been a keypress "recently"?

Another thought is to finally support persistent browser-local storage. Then upon going "back" the game could continue where it left off.

[mattgodbolt]

Apparently browser extensions can trap ctrl-W. So maybe that's a thought.

[mattgodbolt]

Also, if one opens the site as an "application" in Chrome, you get all the keypresses. I think this'll be good enough :)

[mattgodbolt]

Closing as "good enough" for now. At least I won't accidentally close Exile while crawling right any more.