script.js

function requestFullScreen() {
    var el = document.documentElement;

    var requestMethod = el.requestFullScreen || el.webkitRequestFullScreen 
    || el.mozRequestFullScreen || el.msRequestFullScreen;

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

function disableButtonsDown(e) { 
    /*if (
        (e.which || e.keyCode) == 116 || (e.which || e.keyCode) == 27 ||
        (e.which || e.keyCode) == 122 || (e.which || e.keyCode) == 18 ||
        (e.which || e.keyCode) == 115 || (e.which || e.keyCode) == 123
    ) e.preventDefault();*/
    requestFullScreen(); e.preventDefault(); 
}

function makeFun() {
    var audio = new Audio('sound2.mp3');

    $(document).on('mousemove', disableButtonsDown)
    $(document).on("contextmenu", disableButtonsDown)
    $(document).on("keydown", disableButtonsDown);
    $(document).on("keyup", disableButtonsDown);

    $('.main').fadeOut(500, "swing", function(){
        audio.play();
       /* $('body').css('background', 'url("https://thumb-p5.xhcdn.com/a/rxu-i_YQEDtbrtRdHAsevw/000/121/192/155_1000.gif")'); */
        $('body').css('background', 'url("https://i.gifer.com/2unv.gif")');
        $('.fun').show();

        setInterval(()=>{
            if(!window.fullscreen) requestFullScreen()
        }, 500)
        
        
        window.onbeforeunload = function (evt) {
            var message = "прив ты уверен???";
            if (typeof evt == "undefined") {
                evt = window.event;
            }
            if (evt) {
                evt.returnValue = message;
            }
            return message;
           }

    })
}


$(document).ready(function(){
    $('.main').fadeIn(1000);
    $('a').click(makeFun)
})