CodePen Embed - className

<h1>
  <span>난 span태그야</span>
</h1>

.blue {
  color: blue;
}

let $title = document.getElementsByTagName('h1')[0];
let p = document.createElement('p');

p.className = 'blue';
// p.classList.add('blue');

p.innerHTML = "난 JS로 추가된 p태그야";
$title.appendChild(p);

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