FS_FRAME

function makeFrame() {
   ifrm = document.createElement("IFRAME");
   ifrm.setAttribute("src", "#");
   ifrm.setAttribute("id", "main_frame");
   ifrm.style.width = '100%';
   ifrm.style.height = '100%';
   ifrm.style.border = 'none';
   ifrm.style.display = 'none';
   document.body.appendChild(ifrm);
}

function goFullscreen() {
    const button_FS = localStorage.getItem('FullScreen');
    if(button_FS == 'Inativo' || button_FS == null){
        makeFrame();
        const mf = document.getElementById("main_frame");
        if ((document.fullScreenElement !== undefined && document.fullScreenElement === null) || (document.msFullscreenElement !== undefined && document.msFullscreenElement === null) || (document.mozFullScreen !== undefined && !document.mozFullScreen) || (document.webkitIsFullScreen !== undefined && !document.webkitIsFullScreen)) {
            if (mf.requestFullScreen) {
                mf.requestFullScreen();
            } else if (mf.mozRequestFullScreen) {
                mf.mozRequestFullScreen();
            } else if (mf.webkitRequestFullScreen) {
                mf.webkitRequestFullScreen(Element.ALLOW_KEYBOARD_INPUT);
            } else if (mf.msRequestFullscreen) {
                mf.msRequestFullscreen();
        }
            mf.style.display="block";
            localStorage.setItem("FullScreen","Ativo");
        }
    }else if(button_FS == 'Ativo'){
        ////// SÓ FUNCIONA COM O ALERT() AQUI ////////////
        const mf = document.getElementById("main_frame");
        //mf.style.display="none";
        var xframe = document.getElementById("main_frame");
        xframe.parentNode.removeChild(xframe);
        localStorage.setItem("FullScreen","Inativo");
    }
}

function fullscreenChanged() {
    if (document.webkitFullscreenElement == null) {
        const mf = document.getElementById("main_frame");
        mf.style.display="none";
        var xframe = document.getElementById("main_frame");
        xframe.parentNode.removeChild(xframe);
        localStorage.setItem("FullScreen","Inativo");
    }
}

document.onwebkitfullscreenchange = fullscreenChanged;

$(document).ready(function(){
    $('#btn_FS').on('click', function(){
        goFullscreen();
    });
});