Html
<!DOCTYPE html>
<html lang="en">
<head>
<link rel="stylesheet" href="main.css" />
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1" />
<!-- Bootstrap CSS -->
<link
href="https://cdn.jsdelivr.net/npm/bootstrap@5.1.3/dist/css/bootstrap.min.css"
rel="stylesheet"
integrity="sha384-1BmE4kWBq78iYhFldvKuhfTAU6auU8tT94WrHftjDbrCEXSU1oBoqyl2QvZ6jIW3"
crossorigin="anonymous"
/>
<title>Hello, world!</title>
</head>
<body>
<nav class="navbar navbar-light bg-light">
<div class="container-fluid">
<span class="navbar-brand">Navbar</span>
<button class="navbar-toggler" type="button">
<span class="navbar-toggler-icon"></span>
</button>
</div>
</nav>
<ul class="list-group show">
<li class="list-group-item">An item</li>
<li class="list-group-item">A second item</li>
<li class="list-group-item">A third item</li>
<li class="list-group-item">A fourth item</li>
<li class="list-group-item">And a fifth one</li>
</ul>
<script
src="https://cdn.jsdelivr.net/npm/bootstrap@5.1.3/dist/js/bootstrap.bundle.min.js"
integrity="sha384-ka7Sk0Gln4gmtz2MlQnikT1wXgYsOg+OMhuP+IlRH9sENBO0LRn5q+8nbTov4+1p"
crossorigin="anonymous"
>
document.querySelectorAll('.list-group')
document.getElementsByClassName('navbar-toggler')[0].addEventListener('click', function(){
document.getElementsByClassName('list-group')[0].classList.toggle('show');
})
</script>
</body>
</html>
CSS
.list-group {
display: none;
}
.show {
display: block;
}