JSFiddle - React, Tailwind, and code Playground

HTML

<ul>
    <li><a href="#1">Conteudo1</a></li>
    <li><a href="#2">Conteudo2</a></li>
    <li><a href="#3">Conteudo3</a></li>

</ul>


<div class="teste" id="1">
    <p>Teste 1</p>
</div>

<div class="teste" id="2">
    <p>Teste 2</p>
</div>

<div class="teste" id="3">
    <p>Teste 3</p>
</div>

CSS

.teste {
    display: none;
}

JavaScript

function toggle(els, index) {
    return function(e) {
        e.preventDefault();
        for (var i = 0; i < els.length; i++) {
            els[i].style.display = i == index ? 'block' : 'none';
        }
    }
}

var lis = document.querySelectorAll('ul li a');
var testes = document.querySelectorAll('.teste');
for (var i = 0; i < lis.length; i++) {
    lis[i].addEventListener('click', toggle(testes, i));
}