Navbar collapse does not work - bootstrap 4 - php

Question

I have some problems regarding the navbar. The button does not work when the browser is minimized or when I open the website from a phone. Could you please take a look at the code and let me know what the problem is?
<nav class="navbar navbar-expand-lg navbar-light" style="background-color: #caebf2;">
<div class="container-fluid">
<a class="navbar-brand" href="<?php echo base_url(); ?>">HulkGYM</a>
<button class="navbar-toggler" type="button" data-bs-toggle="collapse" data-target="#navbarSupportedContent" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse" id="navbarColor03">
<ul class="navbar-nav me-auto">
<li class="nav-item">
<a class="nav-link active" href="<?php echo base_url(); ?>">Home
</a>
</li>
<li class="nav-item">
<a class="nav-link active" href="<?php echo base_url(); ?>about">About</a>
</li>
<li class="nav-item">
<a class="nav-link active" href="<?php echo base_url(); ?>posts">Forum</a>
</li>
<li class="nav-item">
<a class="nav-link active" href="<?php echo base_url(); ?>categories">Categories</a>
</li>
</ul>
<ul class="nav navbar-nav navbar-right">
<?php if(!$this->session->userdata('logged_in')): ?>
<li><a class="nav-link active" href="<?php echo base_url(); ?>users/register">Register</a></ll>
<li><a class="nav-link active" href="<?php echo base_url(); ?>users/login">Login</a></ll>
<?php endif; ?>
<?php if($this->session->userdata('logged_in')): ?>
<?php if($this->session->userdata('username') == 'rk'): ?>
<li><a class="nav-link active" href="<?php echo base_url(); ?>users/admin">Admin view</a></ll>
<?php endif; ?>
<li><a class="nav-link active" href="<?php echo base_url(); ?>dashboard/index">Profile</a></ll>
<li><a class="nav-link active" href="<?php echo base_url(); ?>posts/create">Create Post</a></ll>
<li><a class="nav-link active" href="<?php echo base_url(); ?>categories/create">Create Category</a></ll>
<li><a class="nav-link active" href="<?php echo base_url(); ?>users/logout">Logout</a></ll>
<?php endif; ?>
</ul>
</div>
</div>
</nav>

Answer 1

How I fixed the problem was that I added
<script src="https://cdn.jsdelivr.net/npm/bootstrap#5.0.2/dist/js/bootstrap.bundle.min.js" integrity="sha384-MrcW6ZMFYlzcLA8Nl+NtUVF0sA7MsXsP1UyJoMp4YLEuNSfAP+JcXn/tWtIaxVXM" crossorigin="anonymous"></script>
in the head tag.
Next step is that I changed data-target="#navbarSupportedContent" aria-controls="navbarSupportedContent" to data-bs-target="#navbarText" aria-controls="navbarText".
Also, with that the id of the second div class needs to be changed. From <div class="collapse navbar-collapse" id="navbarColor03"> to <div class="collapse navbar-collapse" id="navbarText">.
And at the end, the closing tag for <li> was </l1> instead of </li>.
The final code looks like this:
<nav class="navbar navbar-expand-lg navbar-light" style="background-color: #caebf2;">
<div class="container-fluid">
<a class="navbar-brand" href="<?php echo base_url(); ?>">HulkGYM</a>
<button class="navbar-toggler" type="button" data-bs-toggle="collapse" data-bs-target="#navbarText" aria-controls="navbarText" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse" id="navbarText">
<ul class="navbar-nav me-auto">
<li class="nav-item ">
<a class="nav-link active" href="<?php echo base_url(); ?>">Home
</a>
</li>
<li class="nav-item">
<a class="nav-link active" href="<?php echo base_url(); ?>posts">Forum</a>
</li>
<li class="nav-item">
<a class="nav-link active" href="<?php echo base_url(); ?>categories">Categories</a>
</li>
</ul>
<ul class="nav navbar-nav navbar-right">
<?php if(!$this->session->userdata('logged_in')): ?>
<li><a class="nav-link active" href="<?php echo base_url(); ?>users/register">Register</a></li>
<li><a class="nav-link active" href="<?php echo base_url(); ?>users/login">Login</a></li>
<?php endif; ?>
<?php if($this->session->userdata('logged_in')): ?>
<?php if($this->session->userdata('username') == 'rk'): ?>
<li><a class="nav-link active" href="<?php echo base_url(); ?>users/admin">Admin view</a></li>
<?php endif; ?>
<li><a class="nav-link active" href="<?php echo base_url(); ?>dashboard/index">Profile</a></li>
<li><a class="nav-link active" href="<?php echo base_url(); ?>posts/create">Create Post</a></li>
<li><a class="nav-link active" href="<?php echo base_url(); ?>categories/create">Create Category</a></li>
<li><a class="nav-link active" href="<?php echo base_url(); ?>users/logout">Logout</a></li>
<?php endif; ?>
</ul>
</div>
</div>
</nav>