from selenium import webdriver
from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC
driver=webdriver.Firefox()#启动浏览器
driver.implicitly_wait(16)#隐式等待
driver.get('http://localhost/upload/user.php')#打开前台登录页
driver.find_element(By.LINK_TEXT,'EC论坛').click()
# 显式等待：等待条件是浏览器窗口的个数变为2
WebDriverWait(driver,15).until(EC.number_of_windows_to_be(2))

# 切换到新窗口
a=driver.window_handles
driver.switch_to.window(a[-1])
# 点击新窗口内网页里界面右上角的“注册”
driver.find_element(By.XPATH,'//div[@id="umenu"]/a[1]').click()
driver.quit()