Javascript: Toggle browser fullscreen mode

toggle-fullscreen.js

$('body').click(function(event) {
    var el, rfs;

    if ($('body').hasClass('fullscreen')) {
        el = document;
        rfs = el.cancelFullScreen || el.webkitCancelFullScreen || el.mozCancelFullScreen;
        $('body').removeClass('fullscreen');
    } else {
        el = document.documentElement;
        rfs = el.requestFullScreen || el.webkitRequestFullScreen || el.mozRequestFullScreen;
        $('body').addClass('fullscreen');
    }

    if ('undefined' !== typeof rfs && rfs) {
        var a = rfs.call(el);
    } else if ('undefined' !== typeof window.ActiveXObject) {
        var wscript = new ActiveXObject('WScript.Shell');
        if (null !== wscript) {
            wscript.SendKeys('{F11}');
        }
    }
});