JSFiddle - React, Tailwind, and code Playground

by Bahman ParsaManesh

HTML

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Document</title>
   <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/materialize/1.0.0-rc.2/css/materialize.min.css">
</head>
<body>
<ul class="collapsible">
  <li>
   <div class="collapsible-header">Title1</div>
   <div class="collapsible-body" />
  </li>
  <li>
   <div class="collapsible-header">Title2</div>
   <div class="collapsible-body" />
  </li>
</ul>
<br>
<p>Open Collapsible index is : <span id="show"></span></p>
  <script src="https://cdnjs.cloudflare.com/ajax/libs/materialize/1.0.0-rc.2/js/materialize.min.js"></script>
</body>
</html>

JavaScript

$(document).ready(function(){
    $('.collapsible').collapsible();
    
    $(document).on("click","ul.collapsible li", function(){
      var elem = document.querySelectorAll("ul.collapsible li");
      var index = "none"
      for (var i = 0; i < elem.length; i++) {
        if (elem[i].className == "active") {
        	index = i;
        }
        document.getElementById("show").innerHTML = index;
      }
    })
  });