The full form of ASP.NET is Active Server Page Extended.

An Active Server Page (ASP) is an HTML page that includes one or more scripts (small embedded programs) that are processed on a Microsoft Web server before the page is sent to the user. An ASP is somewhat similar to a server-side include or a common gateway interface (CGI) application in that all involve programs that run on the server, usually tailoring a page for the user. Typically, the script in the Web page at the server uses input received as the result of the user’s request for the page to access data from a database and then builds or customizes the page on the fly before sending it to the requestor.

The .ASPX ( Active Server Page Extended ) files are server generated web pages that contain Visual Basic Scripting or C# coding. Most of the time, these pages are created with Microsoft Web Developer and are written for Microsoft’s ASP.NET framework.

The content of .ASPX files includes scripts used by programmers for dynamic Web applications and Websites. These are processed by the Web server which sends the HTML results to the user’s Web Browser. ASPX web pages are also known as “.NET Web Forms”, a named derived from Microsoft’s .NET framework. They are easily identifiable in any Web Browser as their URL will always end in “.aspx”.

How to read or edit .ASPX Files
.ASPX files can be opened using any Web Browser such as Firefox or Safari. However, since this is an active server page extension, Web Browsers will only display the page rendered by the file. The active server components behind it will not be visible.

To view all content users need to open the file in Microsoft Visual Studio. For editing .aspx files all that’s needed is a simple text editor like notepad.