JSFiddle - React, Tailwind, and code Playground

HTML

<mark class=obj><u><a>т</a><strike><b>уп</b><a>и</a></strike><a>к</a></u></mark>

<div id=w></div>

JavaScript

getChildren(document.querySelector('.obj'))

function getChildren(node) {
  [...node.childNodes].forEach(node=>getChildren(node))
	if (node.nodeType === 3) console.log(node.textContent)
}