What happens when an asp.net page is requested from the browser

From the browser the request is sent to IIS. There is an aspnet_isapi.dll in IIS that takes care of serving the request. From this it sends the request to .net framework's worker process. (aspnet_wp.exe)

From IIS there is a mapping that specifies the which isapi is going to process that page. From the website properties, From virtual directory tab, click on 'configuration' button. This shows the application configuration window.



At its core, the ASP.NET execution engine compiles the page into a class, which derives from the code behind class (which in turn derives directly or indirectly from the Page class). Then it injects the newly created class into the execution environment, instantiates it, and executes it.