I want to only allow users with IE8 (not IE6, IE7) or another browser to access my site when logged in.
I followed: http://code.google.com/p/ie6-upgrade-warning/ But
Is this party over? ><
It is, but I think the information here can be updated a bit.
By today's standards, "today" being October 29 of 2013, you can use this meta tag to trigger the latest IE Browser and Document modes and trigger the installation of Google's Chrome Frame in older IEs:
This allows you to server specific IE6/7 styles. Keep in mind that I'm saying 'styles' not 'style sheets', meaning: You'd only use a single CSS file and in it are all your IE6 and IE7 styles. This is to minimize HTTP requests... but that's a totally different conversation.
Anyway, with the above snippet there's no need for scripts or Conditional Comments.
Note: Google Chrome Frame will be retired in January 2014 - more info here.