How to detect whether the browser is online or offline with JavaScript?

Javascript Web Development Object Oriented Programming

To detect whether the browser is online or offline with JavaScript, the code is as follows −

Example

<!DOCTYPE html>
<html>
<body>
<h1>Online or offline with JavaScript example</h1>
<h2>Click the button below to check if you are online or not</h2>
<button onclick="checkOnlineOffline()">Check online/offline</button>
<h2 class="sample"></p>
<script>
   function checkOnlineOffline() {
      if(navigator.onLine===true){
         document.querySelector('.sample').innerHTML = "You are connected to internet"
      } else {
         document.querySelector('.sample').innerHTML = "You are not connected to internet"
      }
   }
</script>
</body>
</html>