1、显式等待
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()
driver.get("http://somedomain/url_that_delays_loading")
try:
element = WebDriverWait(driver, 10).until(
EC.presence_of_element_located((By.ID, "myDynamicElement"))
)
finally:
driver.quit()
除非在10秒内发现元素返回，
否则在抛出TimeoutException之前等待10秒，
WebDriverWait默认每500毫秒调用一次ExpectedCondition，
直到它成功返回，
ExpectedCondition的成功返回类型是布尔值，
对于所有其他ExpectedCondition类型，
返回true或非null返回值。
预期条件，
自动化网页浏览器时经常使用一些常见条件：
from selenium.webdriver.support import expected_conditions as EC
wait = WebDriverWait(driver, 10)
element = wait.until(EC.element_to_be_clickable((By.ID, 'someid')))
下面列出每个的名称：
title_is
title_contains
presence_of_element_located
visibility_of_element_located
visibility_of
presence_of_all_elements_located
text_to_be_present_in_element
text_to_be_present_in_element_value
frame_to_be_available_and_switch_to_it
invisibility_of_element_located
element_to_be_clickable
staleness_of
element_to_be_selected
element_located_to_be_selected
element_selection_state_to_be
element_located_selection_state_to_be
alert_is_present
自定义等待条件：
如果以上的便利方法都不符合你的要求，
您还可以创建自定义等待条件，
可以使用具有__call__方法的类创建自定义等待条件，
该条件在条件不匹配时返回False。
class element_has_css_class(object):
"""期望检查某个元素是否具有特定CSS类
locator-用于查找元素
返回WebElement一旦它具有特定的CSS类
"""
def __init__(self, locator, css_class):
self.locator = locator
self.css_class = css_class
def __call__(self, driver):
element = driver.find_element(*self.locator)
# 查找引用的元素
if self.css_class in element.get_attribute("class"):
return element
else:
return False
wait = WebDriverWait(driver, 10)
element = wait.until(element_has_css_class((By.ID, 'myNewInput'), "myCSSClass"))
# 等到ID = "myNewInput"元素有类"myCSSClass"
2、隐式等待
from selenium import webdriver
driver = webdriver.Firefox()
driver.implicitly_wait(10)
driver.get("http://somedomain/url_that_delays_loading")
myDynamicElement = driver.find_element_by_id("myDynamicElement")