<style>
iframe.noflicker:not(.active) {
display: none
}
</style>
<iframe class="noflicker active" src="https:domain.de?time=0"></iframe>
<iframe class="noflicker" src="https:domain.de?time=0"></iframe>
<script>
var iframes = document.querySelectorAll('iframe.noflicker');
for (var i = 0; i < iframes.length; i++) {
iframes[i].classList.add('firstload');
iframes[i].addEventListener('load', function () {
if (this.classList.contains('firstload')) {
this.classList.remove('firstload');
} else {
var active = document.querySelector('iframe.noflicker.active');
var notactive = document.querySelector('iframe.noflicker:not(.active)');
active.classList.remove('active');
notactive.classList.add('active');
}
});
}
setInterval(function () {
var newURL = document.querySelector('iframe.noflicker.active').src
.replace(/\?time=[\d]+$/, '?time=' + Date.now());
document.querySelector('iframe.noflicker:not(.active)').src = newURL;
}, 3000);
</script>