through the browser object you can check if the game is in portrait or landscape
Using the viewportleft, viewportright, viewportbottom and viewporttop, you can get the exact size of the game and change things accordingly.
It's possible to make completely responsive design this way, scaling layers and or exchanging sprites etc. , depending on the different circumstances.
I told my dentist I had trouble with my teeth and asked her to fix it without looking in my mouth..