(setq inferior-js-mode-hook
(lambda ()
;; We like nice colors
(ansi-color-for-comint-mode-on)
;; Deal with some prompt nonsense
(add-to-list
'comint-preoutput-filter-functions
(lambda (output)
(replace-regexp-in-string "\033\\[[0-9]+[GK]" "" output)))))
\033
is the escape character it prints as ^[
.