How do I chnge fulscreen scaling in events

for example

is on mobile device set fullscren in browser letterbox scale

if not letterbox integer scale

?

thats not possible as far as i know.

you need to choose one.

If you can code javascript you can make 2 versions of your game one with letterbox scale and the other with letterbox integer scale and check the device before loading the game and set which version of the game should be load