With the appropriate extension this can be made seemless. Hit a hotkey get an emacs buffer with the current contents of input box. Write some stuff and save and quit. Input box now contains contents of emacs buffer. Annoyingly this requires a service that sits in the background in chrome because security wont let chrome launch such a process. In chrome you can use text-aid-too. Pentadactyl/vimperator can do it with firefox and others.
