The Display (GUI) Layer

As we said earlier, the GUI Layer (sometimes called the "frontend") balances upon the tenuous border between the world of computers and the world of people. As such, it must perform the often-complex task of translating between human and computer languages.

In its role as translator, the GUI is responsible for two things.

First, the GUI must translate the desires, intentions, needs, and wants of people into executable, logical machine instructions. At the same time, the GUI must also translate computer-generated data into meaningful human-readable information.

This translation, as you might imagine, is no mean feat. In fact, in creating web applications, web developers will spend just as much time building a solid frontend as they will spend developing a dependable backend.

As a web application developer, when concerning yourself with the GUI Layer, you will most likely be concerned primarily with the use and manipulation of "UI Widgets" or "controls". Widgets are interface tools that clients can use to make their intentions, desires, and wants known to the program. Widgets could include buttons, scroll bars, grids, or even clickable images. Widgets should be almost intuitive to you as this is the bit of software we humans most often work with.

For the most part, if you see a new technology, you can recognize it to be a GUI technology if it allows you to create interfaces made up of widgets and allows you to access those widgets as necessary.

Contents:

Web Application Examples
Introduction to the Web Application Development Environment (Tools)
Understanding the Web Browser