JSFiddle - React, Tailwind, and code Playground

HTML

<div id="a">Dummy</div>
<div id="target">Target Text</div>

CSS

#a{
  margin-bottom: 1000px;
}
#target {
  display: none;
}

JavaScript

jQuery(window).scroll(function() {
	if (jQuery(this).scrollTop() > jQuery('#target').offset().top+jQuery('#target').outerHeight()-jQuery(window).height()) {
		jQuery('#target').fadeIn();
  }
});