I use webkit as a headless browser in Python via pyqt / pyside:
http://www.riverbankcomputing.co.uk/software/pyqt/download
http://developer.qt.nokia.com/wiki/Category:LanguageBindings::PySide::Downloads
I particularly like webkit because it is simple to setup. For Ubuntu you just use: sudo apt-get install python-qt4
Here is an example script:
http://webscraping.com/blog/Scraping-JavaScript-webpages-with-webkit/