kurosheeva_check.rb

#!/usr/bin/env ruby
# -*- coding: utf-8 -*-

require 'rubygems'
require 'open-uri'
require 'nokogiri'

uri = <<URI
http://www.buffalo-direct.com/directshop/products/detail.php?product_id=8097
URI

ret = "Yet..."
(Nokogiri::HTML(open(uri).read)/'div.add2cart/form/div.attention').each do |m|
  if m.text.empty? || m.text != "申し訳ございません、在庫がなくなりました。"
    ret = "Go!!"
  end
end

puts ret