How do I detect browser back button pressed on desktop?

How do I detect if the user has pressed the browsers back button when running on the desktop?

the browser "On back button" seems limited to mobile, is there a way to detect it in desktop, so I can add an "Are you sure?" alert before the player exits the game.

Cheers

Ben

Unfortunately, this is part of the browser itself and sounds like a feature that would be out of the scope of the sandbox/canvas the game is executed in.