Firefox is essentially a javascript browser in a browser to begin with, it's just that Firefox .js works on XUL instead of htlm5/css. The Chromeless project is

Firefox is essentially a javascript browser in a browser to begin with, it's just that Firefox .js works on XUL instead of htlm5/css. The Chromeless project is just replacing the XUL chrome frontend with an html5/css frontend. It's kind of a misnomer because by their definition, Firefox already is chromeless, they're just adding a new API.