connection lost code snippet

/**
 * First we can deal with 
 * offline state
 * */
 
 function offlineState() {
     /**
      * The first thing we need to do is
      * get data that user could posibly
      * enter or change, e.g. form elements
      * */
     const data = document.querySelector("#input").value;
     
     /**
      * Our example is simple, but usually here
      * we would collect all data and 
      * put it in array or object.
      * */
      
      localStorage.setItem("data", data);
      
      alert("Your connection is lost! Data is saved locally!");
 }
 
 //Now, let's add event listener
 
 window.addEventListener("offline", offlineState);
 
 
 /**
  * Next thing we will do is create
  * function for when application is back 
  * online
  * */
  
  function onlineState() {
      /**
       * The first thing we will do is
       * get data from localStorage
       * and return it to form
       * */
       
       let data = localStorage.getItem("data");
       
       document.querySelector("#input").value = data;
       
       //Now we notify user that everything is 
       //back online again
       
       alert("We are back online! Keep the good work!");
  }
  
  //Next thing is creating event listener
  
  window.addEventListener("online", onlineState);