SonVu

// ----------------------------------------------------------
// A short snippet for detecting versions of IE in JavaScript
// without resorting to user-agent sniffing
// ----------------------------------------------------------
// If you're not in IE (or IE version is less than 5) then:
//     ie === undefined
// If you're in IE (>=5) then you can determine which version:
//     ie === 7; // IE7
// Thus, to detect IE:
//     if (ie) {}

SonVu

class Foo
  attr_accessor :name, :age, :email, :gender, :height

  def initialize(name, age, email, gender, height)
    @name = name
    @age = age
    @email = email
    @gender = gender
    @height = height
  end

SonVu

class ApplicationController < ActionController::Base
  # Prevent CSRF attacks by raising an exception.
  # For APIs, you may want to use :null_session instead.
  protect_from_forgery with: :exception

  private
  def current_cart
  	Cart.find(session[:cart_id])
  rescue ActiveRecord::RecordNotFound
  	cart = Cart.create

SonVu

_form.html.erb (Product)
 <% f.fields_for :product_images do |builder| %>
      <%= builder.text_field :image %>
    <% end %>

-----------
class Product < ActiveRecord::Base
	has_many :product_images, dependent: :destroy
	accepts_nested_attributes_for :product_images
end

SonVu

class ProductsController < ApplicationController
  before_action :set_product, only: [:show, :edit, :update, :destroy]

  # GET /products
  # GET /products.json
  def index
    @products = Product.all
  end

  # GET /products/1