<!DOCTYPE html>
<html>
<title>W3.CSS</title>
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="https://www.w3schools.com/w3css/4/w3.css">
<body>
<div class="w3-bar w3-red">
<a href="#" class="w3-bar-item w3-button">Home</a>
<a href="#" class="w3-bar-item w3-button w3-hide-small">Link 1</a>
<a href="#" class="w3-bar-item w3-button w3-hide-small">Link 2</a>
<a href="#" class="w3-bar-item w3-button w3-hide-small">Link 3</a>
<a href="javascript:void(0)" class="w3-bar-item w3-button w3-right w3-hide-large w3-hide-medium" onclick="myFunction()">☰</a>
</div>
<div id="demo" class="w3-bar-block w3-red w3-hide w3-hide-large w3-hide-medium">
<a href="#" class="w3-bar-item w3-button">Link 1</a>
<a href="#" class="w3-bar-item w3-button">Link 2</a>
<a href="#" class="w3-bar-item w3-button">Link 3</a>
</div>
<div class="w3-container">
<p>In the example, the navigation bar is replaced with a button (☰) in the top right corner when shown on tablets and mobile devices. When the button is clicked, the links in the bar will vertically stack.</p>
<p>Resize the screen to see the effect.</p>
</div>
<script>
function myFunction() {
var x = document.getElementById("demo");
if (x.className.indexOf("w3-show") == -1) {
x.className += " w3-show";
} else {
x.className = x.className.replace(" w3-show", "");
}
}