word_counter.rb

require "rubygems"
require "open-uri"
require "nokogiri"

def count_word(url)
  text = fetch_text(Nokogiri::HTML(open(url)))

  text.scan(/\w+/).inject(Hash.new(0)) { |count, word|
    count[word.downcase] += 1
    count
  }.sort { |a, b|
    b[1] <=> a[1]
  }
end

def fetch_text(e)
  if e.is_a? Nokogiri::XML::Text
    return e.text
  end

  e.children.inject(String.new) { |text, child|
    text << fetch_text(child)
    text << "\n"
    text
  }
end