How to fill out AJAX form programmatically and scrape results?

Basically, I want to use the Facebook Ads Manager Tool to estimate the number of users targeted by a particular set of targeting parameters. I know there is a published API available, but it is only usable if you are on their advertising application "whitelist." I am sure what I am asking is possible. Plus, it would be interesting to learn more about scraping.Basically, I want to use the Facebook Ads Manag