JSFiddle - React, Tailwind, and code Playground

HTML

<div id="foo">
<iframe src="https://www.zdf.de/">
<p>
Ooops
</p>
</iframe>
</div>
<script>
document.querySelector("#foo iframe").addEventListener("load", function(e) {
   e.target.style.display="block";
});
</script>

CSS

#foo {
  width: 800px; height: 600px; 
  background: url(https://thumb9.shutterstock.com/display_pic_with_logo/2187722/181547168/stock-photo--d-render-of-a-snail-wearing-a-hard-hat-and-carrying-a-hammer-181547168.jpg)
}

#foo iframe { width: 100%; height: 100%; display:none; }