you are absolutely right there are many ways to make the popup depending on the frontend that is used: angular, react/redux however some nice plugins like sweetalert2 does exists to help beginner integrate it faster. There are tons of them if you look for "nodejs popup". However on the ajax part which is what I was talking about, I do recommend to use connect-flash or socket.io to pass the message... of course again there are plenty of nodejs message broker to chose from, but for a beginner those are the easiest to understand in my opinion.