ToolsWeb App Debugger 

Acts like a Web server on your development machine. If you build your Web server application as a Web App Debugger executable, deployment happens automatically during the build process. To debug your application, start it using RunRun. Next, select ToolsWeb App Debugger, click the default URL and select your application in the Web browser that appears. Your application will launch in the browser window, and you can use the IDE to set breakpoints and obtain debugging information.