crawl.rb

require "watir-webdriver"
require "nokogiri"

ff = Watir::Browser.new :ff # variable ff is firefox
ff.goto "https://twitter.com"

# login with your account
ff.button(:type => "submit").click
ff.text_field(:id => "signin-email").set "" # スクリーンネーム
ff.text_field(:id => "signin-password").set "" #　パスワード
ff.button(:class => "submit btn primary-btn js-submit" ).click
ff.goto "https://twitter.com/stmtk_01/followers"

# ログインできなかった場合
if ff.url == "https://twitter.com/login?redirect_after_login=%2Ffollowers%2F"
  form = ff.divs(:id => "page-container")[0]
  form.text_field(:name => "session[username_or_email]").set "stmtk_01"
  form.text_field(:name => "session[password]").set "hzrglnlglpr"
  form.button(:class => "submit btn primary-btn").click
 end
 # ログインし終わり
gets
doc = Nokogiri::HTML.parse(ff.html)
doc.xpath('/html/body//div[@id="page-outer"]//div[@class="AppContainer"]//div[@class="Grid Grid--withGutter"]/    /div[@class="Grid Grid--withGutter"]//div[@class="GridTimeline"]/div[@class="GridTimeline-items"]/div[@class="    Grid Grid--withGutter"]').each do |page|
  docs = Nokogiri::HTML.parse(page.to_s)
  p docs.xpath('/div')
end

ff.close