What is "CGI"?
CGI stands for “Common Gateway Interface”. It's one of the many ways in which interactivity between the user and the web page can be programmed and experienced. It's one of the ways that you when you interact with a web page can be prompted to enter certain information, and consequently drive and actually alter that web page by entering information through this common gateway interface. CGI scripting is used for something as mundane as entering your address on a web page.