CODE EXAMPLE FOR JAVASCRIPT

on button click show collapse div jquery

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<button id="button">Toggle Expand/Collapse</button>
<div id="wrapper">
  <ul id="list">
    <li>Item</li>
    <li>Item</li>
    <li>Item</li>
    <li>Item</li>
  </ul>
</div>