from selenium import webdriver
from selenium.webdriver.common.keys import Keys


browser = webdriver.Firefox()

# Logs into facebook
browser.get('https://www.facebook.com/')
username = browser.find_element_by_name('email')
username.send_keys("some text")
password = browser.find_element_by_name('pass')
password.send_keys("some text")
browser.find_element_by_id("loginbutton").send_keys(u'\ue007')

# Opens new tab, goes to url
browser.execute_script('''window.open("https://facebook.com/", "_blank");''')

# Code below is not executed
username = browser.find_element_by_name('email')
username.send_keys("some text")
password = browser.find_element_by_name('pass')
password.send_keys("some text")