ASP.NET (Active Server Pages) is server side scripting technology that enables scripts to be executed on the web server (IIS).The IIS is component of Windows Server like windows 2000 and XP Professional. The extension for Classic ASP is ".asp" but for ASP.Net the extension is ".ASPX". An ASP.NET Page can contain HTML, XML and scripts.
In simple web page transaction when a browser request a web page, the server in return the HTML file where as in ASP.NET case, the browser request for the ASP.NET page, this request goes to the web server, the web server will pass the this to the ASP.NET engine after the engine will parse the script in the ASP.NET page, convert it to the HTML page and send back to the client's browser
The latest is ASP.NET 2.0 that support new features and controls like
1). Different language support
2). Event Driven
3). Programmable Controls
4). User authentication and other controls
5). Easily deployable
The ASP.NET contains a large number of HTML controls; these controls can be easily managed by the scripts. As earlier mentioned it is event driven, means different events like Load, Click etc are handled by codes.
Another important thing is the complied codes, means at first request; the pages will be complied on the server and keep a cache in the memory. It will help in increased performance.
The configuration in ASP.NET can be done through plain text files
Above article will make you familiar with basic things of ASP.NET
