JSFiddle - React, Tailwind, and code Playground

HTML

<div class="bottomdiv hide" id="footer">
<iframe src="http://example.com" width="990" height="110" scrolling="no"></iframe>
</div>

CSS

.bottomdiv
{
position: absolute;
left:    0;
right:   0;
z-index : 100;
filter : alpha(opacity=100);
POSITION: fixed;
bottom: 0;
}
.hide {
  display: none;
}

JavaScript

setTimeout(function(){
 document.getElementById('footer').classList.remove('hide');
 }, 5000);