js-mode supports the minor mode semantic-mode. You can activate it with M-x semantic-mode.
M-x imenu-add-to-menubar RET Index RET adds a menu item "Index" to the menu bar with submenus Functions and Variables.
You can activate semantic mode by default with the following lines in your init file:
(defun js-setup-semantic ()
"Setup semantic mode for js."
C-m-b (bound to backward-sexp) should go to the matching brace at the same level. There are many other useful code navigation commands too: C-m-f (bound to forward-sexp) and C-m-u which goes up in the code structure. In combination, these commands are very powerful tools for all sorts of code investigation, as well as editing. And they are available in just ...