JSFiddle - React, Tailwind, and code Playground

HTML

<input type='radio' name="myInput">
<span id='a1' style='display: none;'>Joku teksti 1</span>
<br>
<input type='radio'  name="myInput">
<span id='a2' style='display: none;'>Joku teksti 2</span>
<br>
<input type='radio'  name="myInput">
<span id='a3' style='display: none;'>Joku teksti 3</span>

JavaScript

const INPUTS_N = 3;

function showText(ind) {
	for (let i=0; i<INPUTS_N; i++) {
  	let el = document.getElementById('a'+(i+1));
		el.style.display = (i===ind)?'inline-block':'none';
  }
}

for (let [i, x] of document.querySelectorAll("input").entries()) {
	x.onclick = ()=>showText(i);
}