javascript.el

(add-hook 'javascript-mode-hook
          (lambda ()
            (textmate-mode)
            (local-set-key "\r"
                           (lambda () (interactive)
                             (insert-line-before-closing-braces)
                             (newline-and-indent)))))

(defun insert-line-before-closing-braces ()
  (interactive)
  (save-excursion
    (let ((content (buffer-substring (point) (line-end-position))))
      (if (and (> (length content) 0)
               (string= (replace-regexp-in-string ")\\\|}" "" content)  ""))
          (newline-and-indent)))))