使用Javascript在带有IE的Windows XP下检测.NET 4.0

Question

I have a web page that needs to detect if .NET is installed on the user's computer. I don't particularly care about the version of .NET installed. Detection is done via Javascript. Various Googling point to looking for ".NET CLR" in the user agent string. This works well for almost all OS/IE/.NET combinations. Today I found one that it does not work for.

Under Windows XP SP3, IE 8 and .NET 4.0 I get the following for the user agent:

User-Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; .NET4.0C; .NET4.0E)

Before I simply add a check for something like ".NET4.0" I wanted to confirm that this is the proper user agent string I should be getting for my browser/OS/.NET combination above. Does that user agent string look right? Any other .NET identifiers I should be looking for when considering other Windows OS/IE/.NET combinations?

Thanks.

Answer 1

NET CLR is what you should be looking for indeed.You can check it by javascript too at any point inside you code this way:

 if ((navigator.userAgent.indexOf(".NET CLR")>-1)) 
  alert ("CLR available " +navigator.userAgent);
 else
  alert(".NET SDK/Runtime is not available for us from within " + <BR>           "your web browser or your web browser is not supported." + <BR>           " Please check with http://msdn.microsoft.com/net/ for " + <BR>           "appropriate .NET runtime for your machine.");

as shown here: detecting .net availability Be careful tough,user agents can be modified.Even tough your normal user won't most probably