JAVASCRIPT

service worker

service worker is javascript file that run every time.It keeps running even you
close the browser.Due to this we can send push notification,offline mode.
//Register our service worker in index.html
<script>
  if('serviceWorker' in navigator){
  window.addEventListener('load', ()=> {
    //registering of serviceWorker.
  navigator.serviceWorker('./serviceworker.js')
  .then((reg)=> console.log("Success:", reg.scope));
  .catch((err)=> console.log("Failure: ", err));
  })}
 <script>
  
everything ok then we will see Sucess: localhost:3000 in console of browser

service worker.js

if ('serviceWorker' in navigator) {  window.addEventListener('load', function() {    navigator.serviceWorker.register('/sw.js').then(function(registration) {      // Registration was successful      console.log('ServiceWorker registration successful with scope: ', registration.scope);    }, function(err) {      // registration failed :(      console.log('ServiceWorker registration failed: ', err);    });  });}

service worker

const filter = {
  url: [
    {
      urlMatches: 'https://www.google.com/',
    },
  ],
};

chrome.webNavigation.onCompleted.addListener(() => {
  console.info("The user has loaded my favorite website!");
}, filter);