ruby on rails - Drop down filter to sort products by category on index page -

i new rails , building online store. have products model , categories model association: products belong_to category , category has_many products. shoppers have ability select category in drop down , products on index page display items in category.

i able drop down show of categories using form_tag when select on category index page not filter show category.

products index.html.erb:

<%= form_tag('products', :remote => true) %>   <%= select_tag "category", options_from_collection_for_select(category.all, "id", "name"),  { :include_blank => true , :class => "product_select"} %>   <%= submit_tag 'filter' %> <% end %> 

products controller:

  def index     if product.all.collect == (params[:category])         @products= product.send(params[:category])        else         @products = product.order(:title)        end         respond_to |format|         format.html # index.html.erb         format.js # index.js.erb         format.json { render json: @products }        end     end 

application.js:

$(document).ready ->   $(".product_select").on "change", ->     $.ajax       url: "/products"       type: "get"       datatype: "script"       data:         dept_type: $(".product_select").val() 

thanks in advance help, let me know if more information needed.

i not sure if can call db view that(i don't think so). if can shouldn't.

change category.all

here

<%= select_tag "category", options_from_collection_for_select(category.all, "id", "name"),  { :include_blank => true , :class => "product_select"} %> 

to @categories , set in controller.

what value of

 $(".product_select").val() 

also may want many many relationship products , categories. happens when want 1 product in 2 different categories?