JSFiddle - React, Tailwind, and code Playground

HTML

<span id="mySpan">
  My span is here
</span>

CSS

span {
  background-color:#000000;
  color:#ffffff;
}

JavaScript

window.onmouseover=function(e) {
    if (e.target.id=='mySpan') {
    	alert(e.target.id);
    }
}