JSFiddle - React, Tailwind, and code Playground

HTML

<a href="#" class="link">Link</a>
<div class="block">block 1</div>
<div class="block">block 2</div>
<div class="block">block 3</div>
<div class="block">block 4</div>
<div class="block">block 5</div>
<div class="block firststyle">block 6</div>
<div class="block firststyle">block 7</div>
<div class="block firststyle">block 8</div>
<div class="block firststyle">block 9</div>
<div class="block firststyle">block 10</div>

CSS

.firststyle {
  display: none;
}

.visible {
  display: block;
}

JavaScript

document.querySelector(".link").addEventListener("click", event => {
	Array.prototype.forEach.call(document.querySelectorAll(".firststyle"), item => item.classList.toggle("visible"));
}, false);