JSFiddle - React, Tailwind, and code Playground

HTML

<select id="mySelect">
  <option value="1">One</option>
  <option value="2">Two</option>
  <option value="3">Three</option>
</select>

<input type="button" id="btn" value="Show" onclick="findElem()" />

JavaScript

function findElem() {
	var elem = document.getElementById("mySelect");
  alert(elem.options[elem.selectedIndex].text);
}