No sniffing please

Nur ganz kurz:

It is entirely possible to encounter IE8 sending the IE7 User Agent string to the server while using the IE8 Standards Mode rendering engine; conversely, you can encounter the IE8 User Agent string while rendering in IE7’s engine.

If there ever was an argument against merely sniffing the User Agent string to base your code off of, this would be it.

Faruk Ateş: IE8 and the X-UA-Compatible situation