By "cross browser," it looks like the OP means the following minimum versions of mobile browsers which support the Screen Orientation API[1]:

- Chrome 39 - Firefox Mobile (with the moz prefix).

Apparently the API is also supported by the following Desktop browser versions...but I'm not sure this app takes advantage of it:

- Chrome 38 - Firefox (Gecko) - IE 11 - Opera 25

[1] https://developer.mozilla.org/en-US/docs/Web/API/Screen.orie...