If you want to graphically display information coming from the back end, you have to create a user interface. It can be of various types: desktop applications, web applications running in a browser, or mobile applications running in a portable device that displays a graphical interface and interacts with the end user.
Today we live in an Internet-dependent world. With our transactional back end processing thousands of requests, and communicating with heterogeneous systems through web services, we need a presentation layer to interact with end users, preferably one that runs in a browser. Browsers are everywhere, user ...