orientation.js

function functionToCallOnorientationChange() {
    var orientation = screen.mozOrientation;
    
    if (orientation === "portrait-primary" || orientation === "portrait-secondary" ) {
        //do something
    }
    else if if (orientation === "landscape-primary" || orientation === "landscape-secondary" ) {
        //do something else
    }
}

window.screen.onmozorientationchange = functionToCallOnorientationChange;