Field Change Event On A Custom Portlet

I'm wondering if anyone has had success getting a script to fire after a field is changed in a custom portlet. So in my particular case I have a 'select' type field on the portlet and whenever that field is changed I want to be able to invoke a script that manipulates some of the other data in the portlet. I saw someone do this at SuiteWorld so there must be a way. I have tried creating a client script record with my field change function and loading it into the portlet but it does not seem to get triggered