script.js

var a;chrome.runtime.sendMessage({greeting: "hello"}, function(response) {
 a=response.farewell.toString();
});
var diff;
chrome.storage.sync.get('myArray', function(data) {
      for (var i=0;i<data.myArray.length;i++)
      {
      if(a==(data.myArray[i])[0])
      {
         var d=new Date();
        var dateOne = new Date(d.getFullYear(), d.getMonth(),d.getDate(),d.getHours(),d.getMinutes(),0);
        var dateTwo= new Date((data.myArray[i])[3],(data.myArray[i])[4],(data.myArray[i])[5],(data.myArray[i])[6],(data.myArray[i])[7],0);
        var dateThree= new Date(2020,1,1,1,1,0);
        if(dateOne<dateTwo)
        {
        	if(dateTwo.getTime()!=dateThree.getTime())
        	{
            chrome.runtime.sendMessage({redirect: "web.html"});
            // 
            var difference = dateTwo.getTime() - dateOne.getTime(); // This will give difference in milliseconds
            var resultInMinutes = Math.round(difference / 60000);
            // alert(resultInMinutes);
            chrome.storage.sync.set({'diff':resultInMinutes}, function(){
             
              });
            }
        break;
        }
      }
     }
     });