Google Analytics Widget Tracking

I have a form that is generated on a customer's website (lets say customer.com) with javascript that a user fills out and it sends to my site (app.com). I would like to be able to provide information to the customer such as how effective their AdWords campaign was and what search engines users used to end up开发者_StackOverflow filling out the form.

I have started looking at the multiple domain linking option but I am not sure this is the right way.

Is there a way to query what search engine and key words they used and pass this along with the form?

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I'm not entirely sure if this answers your question but this Stack Overflow question details how to extract data from the _utmz cookie (which by default contains the most recent referrer & keyword is present).