JSFiddle - React, Tailwind, and code Playground

HTML

<div id='wrapper' title='example'>
    wrapper<br />
  <div id='content'>
      contents<br />
  </div>
    hello
</div>

JavaScript

window.onload = function() {
    var oDiv = document.getElementById("content");
    oDiv.onmouseover = function() {
        this.parentNode.setAttribute("old_title", this.parentNode.title);
        this.parentNode.title = "";
    };
    oDiv.onmouseout = function() {
        this.parentNode.title = this.parentNode.getAttribute("old_title");
    };    
};