JSFiddle - React, Tailwind, and code Playground

HTML

<button class="accordion">Section 1</button>
<div class="panel"> <p> .... </p> </div>

<button class="accordion">Section 2</button>
<div class="panel"> <p> .... </p> </div>

<button class="accordion">Section 3</button>
<div class="panel"> <p> .... </p> </div>

JavaScript

var acc = document.getElementsByClassName("accordion");
        var i; 
        var that = this;
        for (i = 0; i < acc.length; i++) {
            acc[i].onclick = function(){
                alert(this);
                alert(that);
                this.classList.toggle("active");
                this.nextElementSibling.classList.toggle("show");
          }
        }