There are a bunch of different modules that use a javascript-capable browser as a back-end for scripting (usually mimicking the interface of WWW::Mechanize, an LWP::UserAgent subclass).

See Win32::IE::Mechanize, Mozilla::Mechanize::GUITester, Mozilla::Mechanize and WWW::Selenium

If you're on windows, I believe Win32::IE::Mechanize would be the easiest to install. Mozilla::Mechanize takes some effort, and WWW::Selenium might be your best bet if you're not on windows - but it has a different API.