Javascript and Google Maps API

Hello,
Our current site jubasd.com is using formstack service for the processing of our forms, but would like the use gravityform instead because we can access the form submissions inside wordpress. The form found on this page http://jubasd.com/rates-reservations/to-san-diego-airport is using formstack with some custom javascript for the Zip Code field. It is an input field that checks a hidden drop down field the has zip code and rate (i.e 91950 | $30 ). It also notifies if it is a valid or invalid Zip Code based on the same hidden drop down field. Would there be an issue having gravityforms handle this type of customization?

The other form you can see here http://jubasd.com/rates-reservations/san-diego-county-transportation is using a customized form that is using google map api and checks the distance between the two point and multiplies by a fixed $3 per mile. It doesn't use formstack like the other form just to be clear. Would there be an issue having gravityforms hadle this type of customization?

Thanks for your help.

Regards,
Justin

Its a custom javascript function that a programmer developed for us. The script basically looks at the option field (that is hidden) and checks if the input field is a valid or invalid Zip Code and displays the amount.