I have been asked to present a pop-up to visitors that are hitting our site via specific portal aliases.  Is this possible in JavaScript?

Something like:

* User browses to www.alias.com

* DNN framework redirects to default alias of www.myrealurl.com.

* Pop-up shown because original request was for www.alias.com.

I'm sure I can do this in .NET, but not sure if possible in client side code.  My research so far indicates no.

Thoughts?  Advice?