[2020-10] v3.13+ selenium 例子，真簡潔，真漂亮

自從 seleniun 官網被限制訪問後，且後面一段時間都用得較少，已經有一段時間未持續關注它的動態。時過幾年，發現它有一些非常好的新特性。下文都以 python 作為開發語言。

with 關鍵字

from selenium import webdriver
from selenium.webdriver.common.by import By
from selenium.webdriver.common.keys import Keys
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support.expected_conditions import presence_of_element_located

#This example requires Selenium WebDriver 3.13 or newer
with webdriver.Firefox() as driver:
    wait = WebDriverWait(driver, 10)
    driver.get("https://google.com/ncr")
    driver.find_element(By.NAME, "q").send_keys("cheese" + Keys.RETURN)
    first_result = wait.until(presence_of_element_located((By.CSS_SELECTOR, "h3>div")))
    print(first_result.get_attribute("textContent"))

指定元素，前後左右相對定位

• above
• below
• toLeftOf
• toRightOf
• near

#from selenium.webdriver.support.relative_locator import with_tag_name
passwordField = driver.find_element(By.ID, "password")
emailAddressField = driver.find_element(with_tag_name("input").above(passwordField))

#from selenium.webdriver.support.relative_locator import with_tag_name
emailAddressField = driver.find_element(By.ID, "email")
passwordField = driver.find_element(with_tag_name("input").below(emailAddressField))

#from selenium.webdriver.support.relative_locator import with_tag_name
submitButton = driver.find_element(By.ID, "submit")
cancelButton = driver.find_element(with_tag_name("button").
                                   to_left_of(submitButton))

#from selenium.webdriver.support.relative_locator import with_tag_name
cancelButton = driver.find_element(By.ID, "cancel")
submitButton = driver.find_element(with_tag_name("button").
                                   to_right_of(cancelButton))

near()

Returns the WebElement, which is at most 50px away from the specified element.

#from selenium.webdriver.support.relative_locator import with_tag_name
emailAddressLabel = driver.find_element(By.ID, "lbl-email")    
emailAddressField = driver.find_element(with_tag_name("input").
                                       near(emailAddressLabel))

頁面載入策略（Page loading strategy）

normal

This will make Selenium WebDriver to wait for the entire page is loaded. When set to normal, Selenium WebDriver waits until the load event fire is returned.

By default normal is set to browser if none is provided.

from selenium import webdriver
from selenium.webdriver.chrome.options import Options
options = Options()
options.page_load_strategy = 'normal'
driver = webdriver.Chrome(options=options)
# Navigate to url
driver.get("http://www.google.com")
driver.quit()

eager

This will make Selenium WebDriver to wait until the initial HTML document has been completely loaded and parsed, and discards loading of stylesheets, images and subframes.

When set to eager, Selenium WebDriver waits until DOMContentLoaded event fire is returned.

none

When set to none Selenium WebDriver only waits until the initial page is downloaded.