> Use the Network tab in Chrome Developer Tools to find the AJAX request, you'll usually be greeted by a response in json.

But sometimes you won't. Sometimes you'll be assaulted with a response in a proprietary, obfuscated, or encrypted format. In situations where reverse-engineering the Javascript is unrealistic (perhaps it is equally obfuscated), I recommend Selenium[1][2] for scraping. It hooks a remote control to Firefox, Opera, Chrome, or IE, and allows you to read the data back out.

[1]: http://docs.seleniumhq.org/ [2]: http://docs.seleniumhq.org/projects/webdriver/