Traditionally, in a web application, the client requests the server for a web page. Then, the server responds to the client with the requested HTML page after validating and authenticating the request, if necessary. The next request to the server might occur when a user hits some link on the page, submits a form, and so on. The server again processes the request and sends back the response with another HTML page.
Don't you think instead of getting the whole HTML page (which would be mostly the same look and feel as the last loaded page), we should just get the data we need and update the currently loaded page itself without posting back to the server? Yes, modern web development works in that regard. Today, we just need data from the server on demand using Ajax. After receiving the data, we will just update the UI with JavaScript or a client...
