 elem.requestFullScreen();
        } else if (elem.mozRequestFullScreen) {
            elem.mozRequestFullScreen();
        } else if (elem.webkitRequestFullScreen) {
            elem.webkitRequestFullScreen(Element.ALLOW_KEYBOARD_INPUT);
        } else if (elem.msRequestFullscreen) {
            elem.msRequestFullscreen();
        }
    } else {
        if (document.cancelFullScreen) {
            document.cancelFullScreen();
        } else if (document.mozCancelFullScreen) {
            document.mozCancel