selenium中实现等待页面A加载完毕后，选择下拉选B，B的下拉选加载完毕后点击加载内容吧，然后选择同页的下拉选D，D的下拉选加载完毕后选择下拉选d

在Python中使用Selenium实现等待页面A加载完毕后，选择下拉选B，B的下拉选加载完毕后点击加载内容，然后选择同页的下拉选D，D的下拉选加载完毕后选择下拉选d，可以按照以下步骤：

1. 引入Selenium库和等待方法

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

2. 创建WebDriver对象并加载页面A

driver = webdriver.Chrome()
driver.get("url_of_page_A")

3. 等待页面A加载完毕，选择下拉选B并等待B的下拉选加载完毕

# 等待页面A加载完毕
WebDriverWait(driver, 10).until(EC.presence_of_element_located((By.ID, "id_of_element_on_page_A")))

# 选择下拉选B
select_b = driver.find_element_by_id("id_of_select_B")
select_b.click()

# 等待B的下拉选加载完毕
WebDriverWait(driver, 10).until(EC.presence_of_element_located((By.ID, "id_of_element_on_select_B")))

4. 点击加载内容并等待D的下拉选加载完毕

# 点击加载内容
load_button = driver.find_element_by_id("id_of_load_button")
load_button.click()

# 等待D的下拉选加载完毕
WebDriverWait(driver, 10).until(EC.presence_of_element_located((By.ID, "id_of_element_on_select_D")))

5. 选择下拉选d

select_d = driver.find_element_by_id("id_of_select_d")
select_d.click()