JSFiddle - React, Tailwind, and code Playground

HTML

<div>
  <button class = "b1">
    Clique-me!
  </button>
  
  <button class = "b2" style = "display: none;">
    Outro botão!
  </button>
</div>

JavaScript

var button = document.querySelector(".b1");
var button2 = document.querySelector(".b2");

button.onclick = function() {
 window.open('www.google.com', '_blank');
 button2.style.display = "block";
}