This is an area that could afford some investigation on how ASP.NET delivers different code to different browsers depending on their capabilities. As I’ve said, ASP.NET is pretty smart about handling browser capabilities and rendering code that different browsers can handle.
By default, ASP.NET lumps browsers together as uplevel and downlevel browsers.
Uplevel. Internet Explorer 4.x and up
Downlevel. Basically everything else, including Netscape 6.x