How to detect .Net Framework installed in a web client?

How to detect .Net Framework installed in a web client?

"Whenever .Net framework is installed, it adds a string to Internet Explorer's user agent. For example, I have both 1.0 and 1.1 .Net framework installed. The user agent of my IE browser will be “User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; .NET CLR 1.0.3705; .NET CLR 1.1.4322)”.

The user agent string is added at this reg key [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\5.0\User Agent\Post Platform]

Of course, this works only for IE"

Very nice tip...