Emacs mode to edit JSON

(defun beautify-json ()
  (interactive)
  (let ((b (if mark-active (min (point) (mark)) (point-min)))
        (e (if mark-active (max (point) (mark)) (point-max))))
    (shell-command-on-region b e
     "python -mjson.tool" (current-buffer) t)))

(define-key json-mode-map (kbd "C-c C-f") 'beautify-json)

var myJSObject = {
  attr: {foo: "bar", baz: ["quux", "truc", "pouet"]},
  fooAlert: function (num) {
    alert(this.attr.foo+' '+num);
  }
};
myJSObject.fooAlert(42);