JSFiddle - React, Tailwind, and code Playground

HTML

<h1 id="rt"></h1>

JavaScript

function generate()
{
	var elem = document.getElementById("rt");
  elem.setAttribute('style', 'opacity:0;');
	elem.innerText = '';
  var  tableau_alphabet = [
  	['a', 'e', 'i', 'o', 'u', 'y'],
    ['b','c','d','f','g','h','j','k','l','m','n','p','q','r','s','t','v','w','x','z'],
    ['é','è','ë','ä']
  ];
  var test = "Test création d'un nom simple aléatoire : ";
  test += tableau_alphabet[0][Math.floor(Math.random() * tableau_alphabet[0].length)];
  test += tableau_alphabet[1][Math.floor(Math.random() * tableau_alphabet[1].length)];
  test += tableau_alphabet[2][Math.floor(Math.random() * tableau_alphabet[2].length)];

	elem.innerText = test;
  elem.setAttribute('style', 'opacity:1;');
}
setInterval(generate, 2500);