Strange tabbing behaviour in .erb files

Question

Note that I use spaces for tabs. When I am working in erb files for rails such as example.js.erb or example2.html.erb, I am getting some very odd (and annoying) auto-tabbing behaviour, which I can't figure out.

For example, in a js.erb file I'll type:

function blaah(){  //a comment
  var a = 5;
}

Then I'll press tab on each line and I'll get

function blaah(){  //a comment
                   var a = 5;
}

It would appear as though the 2nd line is attempting to align with the comment above, but for what reason I do not know.

Here is my .emacs file:

(require 'package)
(add-to-list 'package-archives
         '("melpa" . "http://melpa.milkbox.net/packages/")
         t)
(package-initialize)

(load-theme 'misterioso)
(setq inhibit-splash-screen t)

; remove tool/scroll bars
(tool-bar-mode -1)
(scroll-bar-mode -1)

; (row,column) shown in bottom bar
(line-number-mode)
(column-number-mode 1)

; line numbers on the left
(global-linum-mode 1)

; highlight current line num
(require 'hlinum)
(hlinum-activate)
(setq hl-line-sticky-flag nil)

(require 'smartparens)
(smartparens-global-mode t)
(require 'smartparens-config)
(sp-pair "%" "%" :wrap "C-%")

(add-to-list 'load-path "c:/Users/darre00/AppData/Roaming/.emacs.d/web-mode-master")
(require 'web-mode)
(add-to-list 'auto-mode-alist '("\\.phtml\\'" . web-mode))
(add-to-list 'auto-mode-alist '("\\.tpl\\.php\\'" . web-mode))
(add-to-list 'auto-mode-alist '("\\.[agj]sp\\'" . web-mode))
(add-to-list 'auto-mode-alist '("\\.as[cp]x\\'" . web-mode))
(add-to-list 'auto-mode-alist '("\\.erb\\'" . web-mode))
(add-to-list 'auto-mode-alist '("\\.mustache\\'" . web-mode))
(add-to-list 'auto-mode-alist '("\\.djhtml\\'" . web-mode))
(add-to-list 'auto-mode-alist '("\\.html?\\'" . web-mode))
(setq web-mode-enable-auto-pairing nil)

(require 'json-mode)
(add-hook 'json-mode-hook 'hs-minor-mode)

(require 'org)
;; Make org-mode activate automatically for files ending in .org
(add-to-list 'auto-mode-alist '("\\.org$" . org-mode))

(require 'multiple-cursors)
(global-set-key (kbd "C-S-c C-S-c") 'mc/edit-lines)
(global-set-key (kbd "C->") 'mc/mark-next-like-this)
(global-set-key (kbd "C-<") 'mc/mark-previous-like-this)
(global-set-key (kbd "C-c C-<") 'mc/mark-all-like-this)

(require 'expand-region)
(global-set-key (kbd "C-=") 'er/expand-region)
(global-set-key (kbd "C-+") 'er/contract-region)

; scrolling starts 2 lines away from top/bottom
(setq scroll-margin 2
      scroll-preserve-screen-position 1)

; indentation
(setq-default c-basic-offset 2)
(setq-default js-indent-level 2)
(setq-default indent-tabs-mode nil)
(setq-default tab-width 2)
(setq-default web-mode-code-indent-offset 2)

; full file path in title bar
(setq-default frame-title-format '((:eval (if (buffer-file-name)
                                              (abbreviate-file-name (buffer-file-name)) "%f"))))

(ido-mode 1)

; FUNCS
(defun kill-dired-buffers()
  "Kill all dired buffers open."
  (interactive)
  (mapc (lambda (buffer)
      (when (eq 'dired-mode (buffer-local-value 'major-mode buffer))
        (kill-buffer buffer)))
    (buffer-list)
   )
  (message "Killed all dired buffers")
)

(defun toggle-comment ()
  "comment or uncomment region or line"
  (interactive)
  (let (beg end)
    (if (region-active-p)
        (setq beg (region-beginning) end (region-end))
      (setq beg (line-beginning-position) end (line-end-position)))
    (comment-or-uncomment-region beg end)))


; KEYBINDINGS
(global-set-key (kbd "C-c k") 'kill-dired-buffers)
(global-set-key (kbd "C-c /") 'toggle-comment)

Any help is much appreciated.