Detect from browser if specific application is installed

Question

We have an advanced webpage (ASP.NET, C#), and a application which needs to be installed on the client computer in order to utilize the webpage to its fullest. The applicati

Answer 1

When installing your client-side app you could modify the browser configuration to include another request header in HTTP requests and then have the server code look for that header, for example as a supported mime type using the following registry key (for Internet explorer)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\
                                                      Internet Settings\Accepted Documents

I am not sure if Opera and FF use this same key, but they likely have similar configuration options, but this should at least get you on the right track.