JSFiddle - React, Tailwind, and code Playground

HTML

<div>
  <a id="link">Clique aqui para mostrar página</a>
  <iframe id="myIframe" src="user/login">
</iframe>
</div>

CSS

#myIframe { display:none; }

JavaScript

document.getElementById('link').onclick = showIframe;

function showIframe(){
	
  document.getElementById('myIframe').style.display = 'block';
  console.log('called')
}