Getting the content of a URL, after DOM processing and javascript

Is it possible to somehow get the source code of the url, but after DOM processing and the javascript has run.
I'm not talkin on urllib2.urlopen(url).read() since that would give us the same result as viewing the source code on firefox, while what i want is the equivalent to selecting all the page's content by clicking Ctrl+A and them right clicking-> VIew selection source, which is the source of the page after all processing has been made...