iPad / iPhone on orientation change

gistfile1.js

window.onorientationchange = function(){
    var orientation = window.orientation;
    // Look at the value of window.orientation:
    if (orientation === 0){
        // iPad is in Portrait mode.
    }
    else if (orientation === 90){
        // iPad is in Landscape mode. The screen is turned to the left.
    }
    else if (orientation === -90){
        // iPad is in Landscape mode. The screen is turned to the right.
    }
    else if (orientation === 180){
        // Upside down portrait.
    }
}