Testing web apps with Selenium

I’ve seen a couple of people mentioning Selenium, including this link to a great tutorial on Selenium’s standalone mode: Agile Testing: Web app testing with Python part 2: Selenium and Twisted. Selenium does web app acceptance testing using your actual browser. All other testing frameworks I’ve seen do direct HTTP communication and try to emulate a browser, generally neglecting JavaScript. As webapps get more dynamic, something like Selenium seems critical.