A standard script for running programs on a server from a Web page. CGI programs (also called scripts) can be run independently and were designed to be external so they can run under various (possibly different) servers interchangeably. The most common CGI scripts found on the Web are programs that process the information a user enters on a form. For example, whenever you fill in information or choose from a list of radio button options on a Web page, you are most likely filling out a CGI form. Once you hit the "submit" button, the form is sent to the server. There, the form's output is handled by a CGI script, which will call on other programs as necessary (such as a database search engine or a mailer program). Gateways conforming to this specification can be written in any language that produces an executable file. Some of the more popular languages that use CGI include: C or C++, Perl, Python, TCL, shells, and many others.