Backbone.contextmanager

application.js.coffee

window.App = 
  Models: {}
  Collections: {}
  Routers: {}
  Views: {}
  DebugInstances: {}
  context_manager: null
        
  init: ->
    @context_manager = new App.Views.ContextManager
      default: "home"
      contexts:
        "contact":
           ".left-side-panel": "active"
           ".main-content": "program"
           ".right-side-panel": "active"
         "home":
           ".main-content": "home"
           
     new @Routers.HomeRouter()
     new @Routers.ContactRouter()
 
     Backbone.history.start()                                                                        
 
 $ ->
   App.init()                                                                                 
                                                       

context_manager.js.coffee

class App.Views.ContextManager extends Backbone.View
 
  initialize: ({ @default, @contexts, @options }) ->
    @current_context = null
    @prepare() unless @options?.skip_prepare
  
  prepare: ->
    if @options?.element
      @setElement @options?.element
    else
      @setElement $("body")[0]
     
    @switch_to_default_context()
   
  switch_to_default_context: -> @switch_context @default
   
  switch_context: (context) ->
    reverts = if @current_context then _.clone(@contexts[@current_context]) else {}
    for selector, class_name of @contexts[context]
      delete reverts[selector] if reverts[selector] is class_name
      @$(selector).addClass(class_name)
    @$(selector).removeClass(class_name) for selector, class_name of reverts
    @trigger "change:context", @current_context, context
    @current_context = context            
                               

example.haml

.some-top-bar

.page
  .left-side-panel

  .main-content
    .home
    .contact

  .right-side-panel

home_router.js.coffee

class App.Routers.HomeRouter extends Backbone.Router
   
  routes:
    "home": "welcome" 
      
  set_context: ->
    App.context_manager.switch_context "home"
  
  welcome: ->
    @set_context()
    # other stuff related to this route