Selenium NoSuchElementException with Valid XPath (Python)

Question

当我运行下面的代码时，我得到selenium.common.exceptions.NoSuchElementException: Message: no such element: Unable to locate element: {"method":"xpath","selector":"//*[@id="i0"]/input"} (Session info: chrome=83.0.4103.97).

但是，在我的终端中，我可以访问所需的元素：

>>> steam_pressure_field = browser.find_element_by_xpath('//*[@id="i0"]/input')
>>> steam_pressure_field.get_attribute('value')
'0'

正如您在代码的注释部分看到的那样，我尝试等待 3 秒的延迟，看看这是否有所作为。但是，在执行此操作几次后，当我使用延迟时，页面停止加载(也许是一些反机器人功能？

因此，我试图了解这里发生了什么，以及如何成功访问我需要的字段。请问我错过了什么吗？

顺便说一句，divID 似乎不是动态的。

from selenium import webdriver
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.common.by import By
from selenium.common.exceptions import TimeoutException

user_agent = 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.97 Safari/537.36'
options = webdriver.ChromeOptions()
options.add_argument(f'user-agent={user_agent}')
browser = webdriver.Chrome(options=options)
url = 'https://www.tlv.com/global/US/calculator/superheated-steam-table.html?advanced=off'
# delay = 3
# try:
# wait = WebDriverWait(browser, delay)
# wait.until(EC.presence_of_element_located((By.ID, "body")))
# browser.get(url)
# print("Page is ready")
# except TimeoutException:
# print("Loading took too much time")
browser.get(url)
steam_pressure_field = browser.find_element_by_xpath('//*[@id="i0"]/input')
print(steam_pressure_field.get_attribute('value'))

Answer 1

要打印值0，您必须诱导 WebDriverWaitvisibility_of_element_located()，您可以使用以下任一定位器策略：

• 使用CSS_SELECTOR：

  driver.get('https://www.tlv.com/global/US/calculator/superheated-steam-table.html?advanced=off')
  print(WebDriverWait(driver, 20).until(EC.visibility_of_element_located((By.CSS_SELECTOR, "div.inputPanel>div.Controlpanel input.inputText"))).get_attribute("value"))
  

• 使用XPATH：

  driver.get('https://www.tlv.com/global/US/calculator/superheated-steam-table.html?advanced=off')
  print(WebDriverWait(driver, 20).until(EC.visibility_of_element_located((By.XPATH, "//div[@class='InputControlLabel' and text()='Steam Pressure']//following-sibling::input[1]"))).get_attribute("value"))
  

• 控制台输出：

  0
  

• 注意：您必须添加以下导入：

  from selenium.webdriver.support.ui import WebDriverWait
  from selenium.webdriver.common.by import By
  from selenium.webdriver.support import expected_conditions as EC