selenium--QQ邮箱登录

from selenium import webdriver
driver=webdriver.Firefox()
driver.get('https://mail.qq.com')

frame=driver.find_element_by_id('login_frame')
driver.switch_to.frame(frame)

driver.find_element_by_id('u').clear()
driver.find_element_by_id('u').send_keys('username')
driver.find_element_by_id('p').clear()
driver.find_element_by_id('p').send_keys('password')
driver.find_element_by_id('login_button').click()


driver.quit()

一开始一直报如下错误：

selenium.common.exceptions.NoSuchElementException: Message: Unable to locate element: {"method":"id","selector":"u"}

查找资料发现：是因为element包含在frame内，因此需要在查找元素前加入转到frame语句