from time import sleep

from selenium import webdriver

driver = webdriver.Firefox()

driver.get('http://www.baidu.com/')

driver.find_element_by_id('lb').click(); 

driver.find_element_by_id('TANGRAM__PSP_10__unameLoginLink').click()

driver.find_element_by_id('TANGRAM__PSP_10__userName').send_keys('用户名');

driver.find_element_by_id('TANGRAM__PSP_10__password').send_keys('密码'); 

driver.find_element_by_id('TANGRAM__PSP_10__submit').click()

sleep(5)

driver.quit()