look up contact from email address on form

We are in need of some direction with regard scripting/customization. We desire the following functionality:

We have created a custom record we call "Training Survey". After every training class we deliver, we point our users to a link on our website which is a NS Online form. The customer is asked to fill out the survey questions which include the users email address.
The record has several fields...most importantly it has as its parent, the customer field.
We desire to have a script that runs on the online form upon save will read the email address entered, query NS for the contact name and customer (if one exits), then populates the traning survey record with customer and contact information. Currently, we have to manually edit the record to enter the customer and contact information