Python中“无法找到具有xpath的元素”错误

Question

So I am trying to login into my instagram account using phantomJS. However I get a an error on the fourth line ("dom...")

warnings.warn('Selenium support for PhantomJS has been deprecated, please use headless ' Traceback (most recent call last):

and the traceback call concludes with selenium.common.exceptions.InvalidSelectorException: Message: errorMessage":"Unable to locate an element with the xpath expression

What is the cause of this error?

from selenium import webdriver
driver = webdriver.PhantomJS()
driver.get('https://www.instagram.com/accounts/login/')
dom = driver.find_element_by_xpath('//')
import pdb
pdb.set_trace()
username = dom.find_element_by_name('username')
password = dom.find_element_by_name('password')
login_button = dom.find_element_by_xpath('//[@class="_qv64e _gexxb _4tgw8 _njrw0"]')
username.clear()
password.clear()
username.send_keys('your username')
password.send_keys('your password')
login_button.click()
driver.get('https://www.instagram.com/accounts/login')
if 'logged-in' in driver.page_source:
  print 'Logged in'

Answer 1

通过xpath选择html文档中所有元素的正确方法是//*登录按钮的正确，完整xpath是//*[@id="react-root"]/section/main/article/div[2]/div[1]/div/form/span[1]/button