Common Gateway Interface or CGI is the standard for creating interfaces for external programs that use information servers online. To simply put it, CGI creates dynamic output for data or information while plain HTML works on static document management. The program that implements the interface can be executed while a simple HTML document remains unchanged. The CGI allows the customization and tailoring of a web page based on the requests sent from one browser to the server. You can say that CGI is an old innovation, but it is a very versatile innovation that is still widely used and is relevant for many.
A good example of CGI is the functionality to allow people across the world to make queries from the database that you developed. An executable script can be developed so that it would transmit the instructions from the browser to your database, sending back results without the use of gateways to regulate the information. Thus, the CGI serves as a complex gateway, sifting through tons of information from the database and it allows the site to reduce the information on the web page to the requested information from the user.
The CGI uses numerous scripts. In fact, it can be written in any kind of computer language as long as it can be executed. These scripts include Visual Basic, C & C++, PERL, FORTRAN, Python, AppleScript and others. At the moment, PERL is still considered as one of the most widely used scripting tools. You can also use C and C++ which are also widely used by many programmers. A good CGI script should be easy to modify, debug as well as maintain. It is easier to create and manage compared to standard compiled programs and that is why more people prefer the CGI.
The CGI is extremely versatile, which is why it is so popular. It has that flexibility that makes it the standard in running executable files from the servers. The CGI standard shows the unique, authentic web interactivity. For websites, there are endless possibilities to make more compelling online experience. Thus, you will notice that scripts are widely used across various aspects: You can create advertisements, message systems, database manipulation, clocks, calendars, forms, guest books and a bunch of other amazing applications that has made online usage more compelling, all thanks to the power of CGI. CGI makes it easier to create, manage and use the web.