rails 4, ajax partial view return "gsub" error?

i have a dropdown select in my form, when i change my dropdown selection, i trigger an ajax function with script response, my goal is to dynamically load a div to display some html like "checkbox" and "image" tag based on my dropdown, so i do this :

my js :

 $(document).ready(function() 
     {


          $('#apartements_select').change(function() {



                  $.ajax({
                          url: "/units/getfloorplans",
                          data: {
                            apt_id : $('#apartements_select').val()
                          },
                          dataType: "script"
                        });


          });

    });

my controller "units/getfloorplans"

 def getfloorplans

    floorplan = Floorplan.where(:apt_id => params[:apt_id])

    @imgs = floorplan
  end

my partial js file

alert("wei");

$('#divUnitplan').append("

                                <%= escape_javascript( @imgs.each{|i| image_tag i.floorplanphoto.thumb.url}  ) %>
                        ");

my partial js file is called, but somehow i got this error

NoMethodError in Units#getfloorplans

Showing C:/Users/lenovo/Documents/urbanace/urbanacecode/app/views/units/getfloorplans.js.erb where line #5 raised:
undefined method `gsub' for #<Array:0x164792b8>

Rails.root: C:/Users/lenovo/Documents/urbanace/urbanacecode

Application Trace
app/views/units/getfloorplans.js.erb:5:in `_app_views_units_getfloorplans_js_erb__484712465_186925308'

Framework Trace
actionview (4.2.7) lib/action_view/helpers/javascript_helper.rb:27:in `escape_javascript'
actionview (4.2.7) lib/action_view/template.rb:145:in `block in render'
activesupport (4.2.7) lib/active_support/notifications.rb:166:in `instrument'
actionview (4.2.7) lib/action_view/template.rb:333:in `instrument'
actionview (4.2.7) lib/action_view/template.rb:143:in `render'
actionview (4.2.7) lib/action_view/renderer/template_renderer.rb:54:in `block (2 levels) in render_template'
actionview (4.2.7) lib/action_view/renderer/abstract_renderer.rb:39:in `block in instrument'
activesupport (4.2.7) lib/active_support/notifications.rb:164:in `block in instrument'
activesupport (4.2.7) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activesupport (4.2.7) lib/active_support/notifications.rb:164:in `instrument'
actionview (4.2.7) lib/action_view/renderer/abstract_renderer.rb:39:in `instrument'
actionview (4.2.7) lib/action_view/renderer/template_renderer.rb:53:in `block in render_template'
actionview (4.2.7) lib/action_view/renderer/template_renderer.rb:61:in `render_with_layout'
actionview (4.2.7) lib/action_view/renderer/template_renderer.rb:52:in `render_template'
actionview (4.2.7) lib/action_view/renderer/template_renderer.rb:14:in `render'
actionview (4.2.7) lib/action_view/renderer/renderer.rb:46:in `render_template'
actionview (4.2.7) lib/action_view/renderer/renderer.rb:27:in `render'
actionview (4.2.7) lib/action_view/rendering.rb:100:in `_render_template'
actionpack (4.2.7) lib/action_controller/metal/streaming.rb:217:in `_render_template'
actionview (4.2.7) lib/action_view/rendering.rb:83:in `render_to_body'
actionpack (4.2.7) lib/action_controller/metal/rendering.rb:32:in `render_to_body'
actionpack (4.2.7) lib/action_controller/metal/renderers.rb:37:in `render_to_body'
actionpack (4.2.7) lib/abstract_controller/rendering.rb:25:in `render'
actionpack (4.2.7) lib/action_controller/metal/rendering.rb:16:in `render'
actionpack (4.2.7) lib/action_controller/metal/instrumentation.rb:44:in `block (2 levels) in render'
activesupport (4.2.7) lib/active_support/core_ext/benchmark.rb:12:in `block in ms'
C:/RailsInstaller/Ruby2.2.0/lib/ruby/2.2.0/benchmark.rb:303:in `realtime'
activesupport (4.2.7) lib/active_support/core_ext/benchmark.rb:12:in `ms'
actionpack (4.2.7) lib/action_controller/metal/instrumentation.rb:44:in `block in render'
actionpack (4.2.7) lib/action_controller/metal/instrumentation.rb:87:in `cleanup_view_runtime'
activerecord (4.2.7) lib/active_record/railties/controller_runtime.rb:25:in `cleanup_view_runtime'
actionpack (4.2.7) lib/action_controller/metal/instrumentation.rb:43:in `render'
remotipart (1.2.1) lib/remotipart/render_overrides.rb:14:in `render_with_remotipart'
actionpack (4.2.7) lib/action_controller/metal/implicit_render.rb:10:in `default_render'
actionpack (4.2.7) lib/action_controller/metal/implicit_render.rb:5:in `send_action'
actionpack (4.2.7) lib/abstract_controller/base.rb:198:in `process_action'
actionpack (4.2.7) lib/action_controller/metal/rendering.rb:10:in `process_action'
actionpack (4.2.7) lib/abstract_controller/callbacks.rb:20:in `block in process_action'
activesupport (4.2.7) lib/active_support/callbacks.rb:117:in `call'
activesupport (4.2.7) lib/active_support/callbacks.rb:117:in `call'
activesupport (4.2.7) lib/active_support/callbacks.rb:555:in `block (2 levels) in compile'
activesupport (4.2.7) lib/active_support/callbacks.rb:505:in `call'
activesupport (4.2.7) lib/active_support/callbacks.rb:505:in `call'
activesupport (4.2.7) lib/active_support/callbacks.rb:92:in `__run_callbacks__'
activesupport (4.2.7) lib/active_support/callbacks.rb:778:in `_run_process_action_callbacks'
activesupport (4.2.7) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (4.2.7) lib/abstract_controller/callbacks.rb:19:in `process_action'
actionpack (4.2.7) lib/action_controller/metal/rescue.rb:29:in `process_action'
actionpack (4.2.7) lib/action_controller/metal/instrumentation.rb:32:in `block in process_action'
activesupport (4.2.7) lib/active_support/notifications.rb:164:in `block in instrument'
activesupport (4.2.7) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activesupport (4.2.7) lib/active_support/notifications.rb:164:in `instrument'
actionpack (4.2.7) lib/action_controller/metal/instrumentation.rb:30:in `process_action'
actionpack (4.2.7) lib/action_controller/metal/params_wrapper.rb:250:in `process_action'
activerecord (4.2.7) lib/active_record/railties/controller_runtime.rb:18:in `process_action'
actionpack (4.2.7) lib/abstract_controller/base.rb:137:in `process'
actionview (4.2.7) lib/action_view/rendering.rb:30:in `process'
actionpack (4.2.7) lib/action_controller/metal.rb:196:in `dispatch'
actionpack (4.2.7) lib/action_controller/metal/rack_delegation.rb:13:in `dispatch'
actionpack (4.2.7) lib/action_controller/metal.rb:237:in `block in action'
actionpack (4.2.7) lib/action_dispatch/routing/route_set.rb:74:in `call'
actionpack (4.2.7) lib/action_dispatch/routing/route_set.rb:74:in `dispatch'
actionpack (4.2.7) lib/action_dispatch/routing/route_set.rb:43:in `serve'
actionpack (4.2.7) lib/action_dispatch/journey/router.rb:43:in `block in serve'
actionpack (4.2.7) lib/action_dispatch/journey/router.rb:30:in `each'
actionpack (4.2.7) lib/action_dispatch/journey/router.rb:30:in `serve'
actionpack (4.2.7) lib/action_dispatch/routing/route_set.rb:817:in `call'
rack (1.6.4) lib/rack/etag.rb:24:in `call'
rack (1.6.4) lib/rack/conditionalget.rb:25:in `call'
rack (1.6.4) lib/rack/head.rb:13:in `call'
remotipart (1.2.1) lib/remotipart/middleware.rb:27:in `call'
actionpack (4.2.7) lib/action_dispatch/middleware/params_parser.rb:27:in `call'
actionpack (4.2.7) lib/action_dispatch/middleware/flash.rb:260:in `call'
rack (1.6.4) lib/rack/session/abstract/id.rb:225:in `context'
rack (1.6.4) lib/rack/session/abstract/id.rb:220:in `call'
actionpack (4.2.7) lib/action_dispatch/middleware/cookies.rb:560:in `call'
activerecord (4.2.7) lib/active_record/query_cache.rb:36:in `call'
activerecord (4.2.7) lib/active_record/connection_adapters/abstract/connection_pool.rb:653:in `call'
activerecord (4.2.7) lib/active_record/migration.rb:377:in `call'
actionpack (4.2.7) lib/action_dispatch/middleware/callbacks.rb:29:in `block in call'
activesupport (4.2.7) lib/active_support/callbacks.rb:88:in `__run_callbacks__'
activesupport (4.2.7) lib/active_support/callbacks.rb:778:in `_run_call_callbacks'
activesupport (4.2.7) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (4.2.7) lib/action_dispatch/middleware/callbacks.rb:27:in `call'
actionpack (4.2.7) lib/action_dispatch/middleware/reloader.rb:73:in `call'
actionpack (4.2.7) lib/action_dispatch/middleware/remote_ip.rb:78:in `call'
actionpack (4.2.7) lib/action_dispatch/middleware/debug_exceptions.rb:17:in `call'
web-console (2.3.0) lib/web_console/middleware.rb:28:in `block in call'
web-console (2.3.0) lib/web_console/middleware.rb:18:in `catch'
web-console (2.3.0) lib/web_console/middleware.rb:18:in `call'
actionpack (4.2.7) lib/action_dispatch/middleware/show_exceptions.rb:30:in `call'
railties (4.2.7) lib/rails/rack/logger.rb:38:in `call_app'
railties (4.2.7) lib/rails/rack/logger.rb:20:in `block in call'
activesupport (4.2.7) lib/active_support/tagged_logging.rb:68:in `block in tagged'
activesupport (4.2.7) lib/active_support/tagged_logging.rb:26:in `tagged'
activesupport (4.2.7) lib/active_support/tagged_logging.rb:68:in `tagged'
railties (4.2.7) lib/rails/rack/logger.rb:20:in `call'
actionpack (4.2.7) lib/action_dispatch/middleware/request_id.rb:21:in `call'
rack (1.6.4) lib/rack/methodoverride.rb:22:in `call'
rack (1.6.4) lib/rack/runtime.rb:18:in `call'
activesupport (4.2.7) lib/active_support/cache/strategy/local_cache_middleware.rb:28:in `call'
rack (1.6.4) lib/rack/lock.rb:17:in `call'
actionpack (4.2.7) lib/action_dispatch/middleware/static.rb:120:in `call'
rack (1.6.4) lib/rack/sendfile.rb:113:in `call'
railties (4.2.7) lib/rails/engine.rb:518:in `call'
railties (4.2.7) lib/rails/application.rb:165:in `call'
rack (1.6.4) lib/rack/lock.rb:17:in `call'
rack (1.6.4) lib/rack/content_length.rb:15:in `call'
rack (1.6.4) lib/rack/handler/webrick.rb:88:in `service'
C:/RailsInstaller/Ruby2.2.0/lib/ruby/2.2.0/webrick/httpserver.rb:138:in `service'
C:/RailsInstaller/Ruby2.2.0/lib/ruby/2.2.0/webrick/httpserver.rb:94:in `run'
C:/RailsInstaller/Ruby2.2.0/lib/ruby/2.2.0/webrick/server.rb:294:in `block in start_thread'

Full Trace
actionview (4.2.7) lib/action_view/helpers/javascript_helper.rb:27:in `escape_javascript'
app/views/units/getfloorplans.js.erb:5:in `_app_views_units_getfloorplans_js_erb__484712465_186925308'
actionview (4.2.7) lib/action_view/template.rb:145:in `block in render'
activesupport (4.2.7) lib/active_support/notifications.rb:166:in `instrument'
actionview (4.2.7) lib/action_view/template.rb:333:in `instrument'
actionview (4.2.7) lib/action_view/template.rb:143:in `render'
actionview (4.2.7) lib/action_view/renderer/template_renderer.rb:54:in `block (2 levels) in render_template'
actionview (4.2.7) lib/action_view/renderer/abstract_renderer.rb:39:in `block in instrument'
activesupport (4.2.7) lib/active_support/notifications.rb:164:in `block in instrument'
activesupport (4.2.7) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activesupport (4.2.7) lib/active_support/notifications.rb:164:in `instrument'
actionview (4.2.7) lib/action_view/renderer/abstract_renderer.rb:39:in `instrument'
actionview (4.2.7) lib/action_view/renderer/template_renderer.rb:53:in `block in render_template'
actionview (4.2.7) lib/action_view/renderer/template_renderer.rb:61:in `render_with_layout'
actionview (4.2.7) lib/action_view/renderer/template_renderer.rb:52:in `render_template'
actionview (4.2.7) lib/action_view/renderer/template_renderer.rb:14:in `render'
actionview (4.2.7) lib/action_view/renderer/renderer.rb:46:in `render_template'
actionview (4.2.7) lib/action_view/renderer/renderer.rb:27:in `render'
actionview (4.2.7) lib/action_view/rendering.rb:100:in `_render_template'
actionpack (4.2.7) lib/action_controller/metal/streaming.rb:217:in `_render_template'
actionview (4.2.7) lib/action_view/rendering.rb:83:in `render_to_body'
actionpack (4.2.7) lib/action_controller/metal/rendering.rb:32:in `render_to_body'
actionpack (4.2.7) lib/action_controller/metal/renderers.rb:37:in `render_to_body'
actionpack (4.2.7) lib/abstract_controller/rendering.rb:25:in `render'
actionpack (4.2.7) lib/action_controller/metal/rendering.rb:16:in `render'
actionpack (4.2.7) lib/action_controller/metal/instrumentation.rb:44:in `block (2 levels) in render'
activesupport (4.2.7) lib/active_support/core_ext/benchmark.rb:12:in `block in ms'
C:/RailsInstaller/Ruby2.2.0/lib/ruby/2.2.0/benchmark.rb:303:in `realtime'
activesupport (4.2.7) lib/active_support/core_ext/benchmark.rb:12:in `ms'
actionpack (4.2.7) lib/action_controller/metal/instrumentation.rb:44:in `block in render'
actionpack (4.2.7) lib/action_controller/metal/instrumentation.rb:87:in `cleanup_view_runtime'
activerecord (4.2.7) lib/active_record/railties/controller_runtime.rb:25:in `cleanup_view_runtime'
actionpack (4.2.7) lib/action_controller/metal/instrumentation.rb:43:in `render'
remotipart (1.2.1) lib/remotipart/render_overrides.rb:14:in `render_with_remotipart'
actionpack (4.2.7) lib/action_controller/metal/implicit_render.rb:10:in `default_render'
actionpack (4.2.7) lib/action_controller/metal/implicit_render.rb:5:in `send_action'
actionpack (4.2.7) lib/abstract_controller/base.rb:198:in `process_action'
actionpack (4.2.7) lib/action_controller/metal/rendering.rb:10:in `process_action'
actionpack (4.2.7) lib/abstract_controller/callbacks.rb:20:in `block in process_action'
activesupport (4.2.7) lib/active_support/callbacks.rb:117:in `call'
activesupport (4.2.7) lib/active_support/callbacks.rb:117:in `call'
activesupport (4.2.7) lib/active_support/callbacks.rb:555:in `block (2 levels) in compile'
activesupport (4.2.7) lib/active_support/callbacks.rb:505:in `call'
activesupport (4.2.7) lib/active_support/callbacks.rb:505:in `call'
activesupport (4.2.7) lib/active_support/callbacks.rb:92:in `__run_callbacks__'
activesupport (4.2.7) lib/active_support/callbacks.rb:778:in `_run_process_action_callbacks'
activesupport (4.2.7) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (4.2.7) lib/abstract_controller/callbacks.rb:19:in `process_action'
actionpack (4.2.7) lib/action_controller/metal/rescue.rb:29:in `process_action'
actionpack (4.2.7) lib/action_controller/metal/instrumentation.rb:32:in `block in process_action'
activesupport (4.2.7) lib/active_support/notifications.rb:164:in `block in instrument'
activesupport (4.2.7) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activesupport (4.2.7) lib/active_support/notifications.rb:164:in `instrument'
actionpack (4.2.7) lib/action_controller/metal/instrumentation.rb:30:in `process_action'
actionpack (4.2.7) lib/action_controller/metal/params_wrapper.rb:250:in `process_action'
activerecord (4.2.7) lib/active_record/railties/controller_runtime.rb:18:in `process_action'
actionpack (4.2.7) lib/abstract_controller/base.rb:137:in `process'
actionview (4.2.7) lib/action_view/rendering.rb:30:in `process'
actionpack (4.2.7) lib/action_controller/metal.rb:196:in `dispatch'
actionpack (4.2.7) lib/action_controller/metal/rack_delegation.rb:13:in `dispatch'
actionpack (4.2.7) lib/action_controller/metal.rb:237:in `block in action'
actionpack (4.2.7) lib/action_dispatch/routing/route_set.rb:74:in `call'
actionpack (4.2.7) lib/action_dispatch/routing/route_set.rb:74:in `dispatch'
actionpack (4.2.7) lib/action_dispatch/routing/route_set.rb:43:in `serve'
actionpack (4.2.7) lib/action_dispatch/journey/router.rb:43:in `block in serve'
actionpack (4.2.7) lib/action_dispatch/journey/router.rb:30:in `each'
actionpack (4.2.7) lib/action_dispatch/journey/router.rb:30:in `serve'
actionpack (4.2.7) lib/action_dispatch/routing/route_set.rb:817:in `call'
rack (1.6.4) lib/rack/etag.rb:24:in `call'
rack (1.6.4) lib/rack/conditionalget.rb:25:in `call'
rack (1.6.4) lib/rack/head.rb:13:in `call'
remotipart (1.2.1) lib/remotipart/middleware.rb:27:in `call'
actionpack (4.2.7) lib/action_dispatch/middleware/params_parser.rb:27:in `call'
actionpack (4.2.7) lib/action_dispatch/middleware/flash.rb:260:in `call'
rack (1.6.4) lib/rack/session/abstract/id.rb:225:in `context'
rack (1.6.4) lib/rack/session/abstract/id.rb:220:in `call'
actionpack (4.2.7) lib/action_dispatch/middleware/cookies.rb:560:in `call'
activerecord (4.2.7) lib/active_record/query_cache.rb:36:in `call'
activerecord (4.2.7) lib/active_record/connection_adapters/abstract/connection_pool.rb:653:in `call'
activerecord (4.2.7) lib/active_record/migration.rb:377:in `call'
actionpack (4.2.7) lib/action_dispatch/middleware/callbacks.rb:29:in `block in call'
activesupport (4.2.7) lib/active_support/callbacks.rb:88:in `__run_callbacks__'
activesupport (4.2.7) lib/active_support/callbacks.rb:778:in `_run_call_callbacks'
activesupport (4.2.7) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (4.2.7) lib/action_dispatch/middleware/callbacks.rb:27:in `call'
actionpack (4.2.7) lib/action_dispatch/middleware/reloader.rb:73:in `call'
actionpack (4.2.7) lib/action_dispatch/middleware/remote_ip.rb:78:in `call'
actionpack (4.2.7) lib/action_dispatch/middleware/debug_exceptions.rb:17:in `call'
web-console (2.3.0) lib/web_console/middleware.rb:28:in `block in call'
web-console (2.3.0) lib/web_console/middleware.rb:18:in `catch'
web-console (2.3.0) lib/web_console/middleware.rb:18:in `call'
actionpack (4.2.7) lib/action_dispatch/middleware/show_exceptions.rb:30:in `call'
railties (4.2.7) lib/rails/rack/logger.rb:38:in `call_app'
railties (4.2.7) lib/rails/rack/logger.rb:20:in `block in call'
activesupport (4.2.7) lib/active_support/tagged_logging.rb:68:in `block in tagged'
activesupport (4.2.7) lib/active_support/tagged_logging.rb:26:in `tagged'
activesupport (4.2.7) lib/active_support/tagged_logging.rb:68:in `tagged'
railties (4.2.7) lib/rails/rack/logger.rb:20:in `call'
actionpack (4.2.7) lib/action_dispatch/middleware/request_id.rb:21:in `call'
rack (1.6.4) lib/rack/methodoverride.rb:22:in `call'
rack (1.6.4) lib/rack/runtime.rb:18:in `call'
activesupport (4.2.7) lib/active_support/cache/strategy/local_cache_middleware.rb:28:in `call'
rack (1.6.4) lib/rack/lock.rb:17:in `call'
actionpack (4.2.7) lib/action_dispatch/middleware/static.rb:120:in `call'
rack (1.6.4) lib/rack/sendfile.rb:113:in `call'
railties (4.2.7) lib/rails/engine.rb:518:in `call'
railties (4.2.7) lib/rails/application.rb:165:in `call'
rack (1.6.4) lib/rack/lock.rb:17:in `call'
rack (1.6.4) lib/rack/content_length.rb:15:in `call'
rack (1.6.4) lib/rack/handler/webrick.rb:88:in `service'
C:/RailsInstaller/Ruby2.2.0/lib/ruby/2.2.0/webrick/httpserver.rb:138:in `service'
C:/RailsInstaller/Ruby2.2.0/lib/ruby/2.2.0/webrick/httpserver.rb:94:in `run'
C:/RailsInstaller/Ruby2.2.0/lib/ruby/2.2.0/webrick/server.rb:294:in `block in start_thread'



Request parameters
{"apt_id"=>"122",
 "_"=>"1472555205634"}

Session dump
_csrf_token: "***"
session_id: "*****"

Env dump
GATEWAY_INTERFACE: "CGI/1.1"
HTTP_ACCEPT: "text/javascript, application/javascript, application/ecmascript, application/x-ecmascript, */*; q=0.01"
HTTP_ACCEPT_ENCODING: "gzip, deflate, sdch"
HTTP_ACCEPT_LANGUAGE: "en-US,en;q=0.8"
REMOTE_ADDR: "127.0.0.1"
REMOTE_HOST: "127.0.0.1"
SERVER_NAME: "localhost"
SERVER_PROTOCOL: "HTTP/1.1"

Response headers
None

i really have no idea what goes wrong, need some help to get this to work.

oh btw, i am really open if you have a better solution, kindly provide an example. many thanks