"I've recently switched to Conkeror as my primary browser. It started life as a Firefox extension, but nowadays it's a standalone app built on top of Mozilla's xulrunner, so it uses the Gecko rendering engine. [...] In other words, it really is not just an emacs-like frontend to Gecko/Firefox, but is a full platform on top of xulrunner for writing interactive applications in javascript/html/css like emacs..."