As far as I know its *not* possible to launch an external executive with html/js/whatever web related (normally). Http is shown in the browser and does not get access from anything outside the runtime. Mainly on security purposes, otherwise you could force a visitor, downloading something (js or other scripts), even a image file or something, containing some ad-/malware/virus/whatever code and forcing the client in the next second to execute this code which is decrypted as an executive file.
Maybe things changed in the past year, but this is what I know about that topic :/
Maybe its possible to do such with using an active-x component when you get it somehow implemented into the project/files, but that would make your site "IE-only".