It's easy to execute a Perl script from a HTML page. You can do this using SSI (depending on server configuration) or just open a script using a link or a form.
SSI:
<!--#exec cgi="path_to_script/myfile.pl"-->
As far as ASP goes, I honestly don't know how to do it, but I'm sure it's possible. And it shouldn't be too hard.
It also means more overhead when the server is processing it because now it must run through an additional parser it did not have to before.
Make sense?