<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<link rel="stylesheet" href="style.css">
<link href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/5.13.0/css/all.min.css" rel="stylesheet">
*{
margin: 0;
padding: 0;
box-sizing: border-box;
}
header{
position: relative;
width: 100%;
height: 80px;
background-color: rgb(153, 153, 153);
display: flex;
justify-content: space-between;
align-items: center;
}
header a img{
width: 100px;
padding-top: 20px;
}
header #menu-bar {
list-style-type: none;
}
header ul li{
display: flex;
list-style: none;
}
header ul li a{
text-decoration: none;
padding: 0 10px;
color: white;
font-size: 18px;
text-transform: uppercase;
letter-spacing:1.4px;
}
.nav-bar{
border: 2px solid white;
text-align: center;
margin-right: 10px;
display:none;
}
.fa-bars{
color: white;
font-size: 18px;
padding: 5px;
}
.active{
display: block;
background:red
}
@media only screen and (max-width:600px){
header ul {
display:none;
margin-top: 200px;
width: 100vw;
text-align: center;
background:skyblue;
}
.nav-bar{
display:block;
}
header ul li{
flex-direction: column;
}
header ul li a{
color: black;
padding-top: 10px;
}
.navbar {
display: none;
}
}
</head>
<body>
<!-- Adding Navbar -->
<header>
<a href="#logo" class="logo">
<img src="./img/Logo.png" alt="logo">
</a>
<ul id="menu-bar">
<li>
<a href="#">Home</a>
<a href="#">About</a>
<a href="#">Services</a>
<a href="#">Contact</a>
</li>
</ul>
<a href="" class="nav-bar" id="navBtn"><i class=" fas fa fa-bars"></i></a>
</header>
<script>
let mainNav = document.getElementById('menu-bar');
let navBarToggle = document.getElementById('navBtn');
<!--I am facing a problem in this line-->
navBarToggle.addEventListener('click', function (){
mainNav.classList.add('active');
});
</body>
</html>