     @mainMenu = options.mainMenu if options.mainMenu?
     @mainMenu = document.querySelector @mainMenu if typeof @mainMenu is "string"
 
-    os = @detectUserAgent()
-    @transitionAnimation = false if os.android and os.version <= '2.1'
+    @detectUserAgent()
+    @transitionAnimation = false if @os.android and @os.version <= '2.1'
 
     @hideUrlBar() if options.hideUrlbar
 

  currentPage: ''
  targetPage: ''
  startPage: ''

  isTransitioning: false
  menuOpen: false

    os.opera = (if userAgent.match(/Opera Mobi/) then true else false)
    os.fennec = (if userAgent.match(/fennec/i) then true else false)
    os.desktop = not (os.ios or os.android or os.blackberry or os.opera or os.fennec)
    @os = os

  # Private: Hide the URL bar in mobile browsers.
  # 
