It is a computer that is used to provide information services using the protocols and tools popularized on the internet.

The Microsoft Internet Information Server is a Web Server software that runs as a service on Windows NT server.

IIS provides three basic services to users:

1. Web Services : IIS functions as a WWW publishing server.
2. FTP Services: IIS functions as a FTP publishing server.
3. Gopher Services: IIS functions as a Gopher publishing server.

On the Web documents are served up as a set of pages with links between them, a "web" of information. Web pages are written in a tagged format called the Hypertext Markup Language (HTML). Web pages can contain text, images, videos, sounds, animation, even 3D worlds. To connect to other pages on the web you click on enabled text or graphics, which are hyperlinks to other locations (Internet addresses).

A link to a web page is an example of a static document. You can also have links that process information and request services. For example, you can have a fill-in field in a form on a Web page and a button. The button can take the information in the field and pass it along to a server for further processing. The server can then run a script or post a query to a database and return information creating a dynamic page. Figure below shows an example of how a browser communicates with IIS and how IIS communicates with a database like SQL server using Active Server Pages (ASP) technology.

Before ASP technology came into existence, interactive web pages were written using CGI (Common Gateway Interface) technolology. These programs were written in languages that supported standard input and standard output such as C, C++ and VC++. Thus the development of a typical interactive web application meant compiling an executable application using a traditional application development environment such as Visual C++. After the applicaion was compiled, it was copied to a CGI directory of the Web Server. Even the slightest change to the application meant recompiling the entire application and replacing the previous version of the executable file. This is unnecessarily resource intensive in a production environment. Active Server Pages solves this problem by providing a more direct and easier way to create web applications.

Active Server Pages are supported by IIS. By default, ASP only supports VBScript and JavaScript. Support for additional scripting languages such as Perl has to be added.

1. Server Side Script : This script runs on the server side.
2. Client Side Script : This script runs on the client side.

When a client tries to access an ASP, the HTML text along with client side script is ignored by the Web Server and is sent to the client while the server side script executes on the server.

This concept can be clarified with the help of an example of an Order Form for a product such as School Uniforms. Suppose, the client (a wholesale dealer for uniforms) can order a certain quantity of school uniforms of a particular colour and quality via the internet. The form will typically consist of entry fields such as product ID, colour, quality, price and quantity to be ordered along with client details such as name of organisation, address, payment details etc. and a command button to order the material. The HTML will consist of formats of the form design, the client side script will typically consist of script for validations of data being entered and the server side script will be executed once the client presses the order command button which will update the order table in the database residing on the server.

The author Mrs. Madhavi Karnik, is a senior member of the ECOMMERCE Team at FANDS and can be contacted at articles@fandsindia.com .