Yes it could, but since the lion's share of client side scripting is done in JS, I thought it the appropriate answer. (Particularly when Perl is the server-side language. I would think that most people using VBScript would also be using ASP).
I've been doing web work since the web began and I have never once been involved in or even heard of the project that uses PerlScript for the client side.
-pete
"Worry is like a rocking chair. It gives you something to do, but it doesn't get you anywhere."