Since FVTT 0.8.6 you can disable the canvas within the settings on the client side.
This produces some errors in the console since keybindings.js#L114 and L150 use canvas.app and canvas.controls properties which are undefined when the canvas is disabled.
Adding a check for game.settings.get("core", "noCanvas") which should be false before initialization of your code should prevent these errors.
Since FVTT 0.8.6 you can disable the canvas within the settings on the client side. This produces some errors in the console since keybindings.js#L114 and L150 use canvas.app and canvas.controls properties which are undefined when the canvas is disabled.
Adding a check for
game.settings.get("core", "noCanvas")
which should be false before initialization of your code should prevent these errors.