var iframe = document.createElement('iframe');
iframe.style = "width:100%; border:none";
iframe.id = "ZZSS-calendar-frame";
iframe.setAttribute('allowTransparency', true);
iframe.frameBorder = "0";
iframe.scrolling = "no";
iframe.src = "https://zzss.net.pl/index.php?page=calendar&mode=plain&year=2022";
document.getElementById('ZZSS-calendar').appendChild(iframe);


window.addEventListener('message', function (event) {
if (event.origin == 'https://zzss.net.pl') {
document.getElementById('ZZSS-calendar-frame').height = event.data;
}
}, false);