JSFiddle - React, Tailwind, and code Playground

HTML

<div id="qwe" class="blue" data-tag="<span class='red'>red</span>">
  blue
</div>
<div id="asd">

</div>

CSS

.blue {
  color: blue;
}

.red {
  color: red;
}

JavaScript

div = document.getElementById('qwe');
  div2 = document.getElementById('asd');
  span = div.getAttribute('data-tag');
  div2.innerHTML = span;