If you can guarantee that:

• Your users will only use IE on Win32
• Your users will install ActivePerl

Then, you can use PerlScript to build a full webserver within the webpage itself. There's been some ideas about this floating around the Net for at least 5 years now. But, because of the restrictions I outlined above, this is only useful for some intranet application. So, the idea never took off.

As for security ... what avenues of attack do you foresee? The big question is "Do you have anything going over a wire?" If you don't (and loopback doesn't count), then you don't need https, which is good because it's a pain in the ass to implement and/or deploy. (There's a reason why Apache uses OpenSSL instead of writing its own.)

As for using the browser as your GUI ... I wouldn't. Browsers right now suck ass as GUI environments. The only benefit they have is that a monkey can do something that looks okay. To get anything seriously good, you have to move out of the browser and into a real GUI environment like wxPerl or Tk. To me, the measure of a GUI environment is "Can you implement FreeCiv?" If you can't, then you're not a real GUI environment. Browsers are coming close, but they're not there yet.