JSFiddle - React, Tailwind, and code Playground

HTML

<select name="1" id="1" onchange="kekus();">
  <option></option>
  <option value="1">1</option>
  <option value="2">2</option>
  <option value="3">3</option>
  <option value="4">4</option>
 </select>
 <span id="123">Ололо</span>

JavaScript

function kekus(){
var x = document.getElementById('1').selectedIndex;
if (x != "2"){
 document.getElementById('123').style.display.none;
 }
 }