pip install selenium

# _*_coding:utf-8_*_ 
from selenium import webdriver
import datetime 
import time


driver = webdriver.Firefox()

def login(uname, pwd):
 driver.get("http://www.jd.com")
 driver.find_element_by_link_text("你好，请登录").click()
 time.sleep(3)
 driver.find_element_by_link_text("账户登录").click()
 driver.find_element_by_name("loginname").send_keys(uname)
 driver.find_element_by_name("nloginpwd").send_keys(pwd)
 driver.find_element_by_id("loginsubmit").click()
 time.sleep(3)
 driver.get("https://cart.jd.com/cart.action")
 time.sleep(3)
 driver.find_element_by_link_text("去结算").click()
 now = datetime.datetime.now()
 print now.strftime('%Y-%m-%d %H:%M:%S')
 print 'login success'


# buytime = '2016-12-27 22:31:00' 
def buy_on_time(buytime):
 while True:
  now = datetime.datetime.now()
  if now.strftime('%Y-%m-%d %H:%M:%S') == buytime:
   driver.find_element_by_id('order-submit').click()
   time.sleep(3)
   print now.strftime('%Y-%m-%d %H:%M:%S')
   print 'purchase success'
  time.sleep(0.5)


# entrance
login('username', 'password')
buy_on_time('2017-01-01 14:00:00')