Selenium - wait until element is present, visible and interactable

问题

I have a selenium script (python) that clicks a reply button to make the class anonemail appear. The time it takes for the class anonemail to appear varies. Because of that I have to use sleep until the element has appeared. I want to wait until the class has appeared instead of using sleep. I have heard about wait commands, but I don't know how to use them.

This is what I have thus far:

browser.find_element_by_css_selector(".reply-button").click()
sleep(5)
email=browser.find_element_by_css_selector(".anonemail").get_attribute("value")

回答1:

As per the best practices:

If your usecase is to validate the presence of any element you need to induce WebDriverWait setting the expected_conditions as presence_of_element_located() which is the expectation for checking that an element is present on the DOM of a page. This does not necessarily mean that the element is visible. So the effective line of code will be:
```
WebDriverWait(browser, 20).until(EC.element_to_be_clickable((By.CSS_SELECTOR, ".reply-button"))).click()
```
If your usecase is to extract any attribute of any element you need to induce WebDriverWait setting the expected_conditions as visibility_of_element_located(locator) which is an expectation for checking that an element is present on the DOM of a page and visible. Visibility means that the element is not only displayed but also has a height and width that is greater than 0. So in your usecase effectively the line of code will be:
```
email = WebDriverWait(driver, 20).until(EC.visibility_of_element_located((By.CSS_SELECTOR, "element_css"))).get_attribute("value")
```
If your usecase is to invoke click() on any element you need to induce WebDriverWait setting the expected_conditions as element_to_be_clickable() which is an expectation for for checking an element is visible and enabled such that you can click it. So in your usecase effectively the line of code will be:
```
WebDriverWait(browser, 20).until(EC.element_to_be_clickable((By.CSS_SELECTOR, ".reply-button"))).click()
```

References

You can find a couple of detailed discussion in:

WebDriverWait not working as expected
Selenium: Check for the presence of element

回答2:

You can use waits. Check for more info on this link: selenium watis

On the example bellow we are waiting 10 seconds for the element to be visible, using the function visibility_of_element_located.

driver = webdriver.Firefox()
driver.get("http://somedomain/url_that_delays_loading")
try:
    element = WebDriverWait(driver, 10).until(
        EC.visibility_of_element_located((By.ID, "myDynamicElement"))
    )
finally:
    driver.quit()

回答3:

You can use implicitly_wait

from selenium import webdriver

driver = webdriver.Firefox()
driver.implicitly_wait(15)
driver.get("http://url")
driver.find_element_by_id("id_of_element").click()

It waits until element is loaded.

In your case implementation would be,

browser.implicitly_wait(10)
browser.find_element_by_css_selector(".reply-button").click()
email=browser.find_element_by_css_selector(".anonemail").get_attribute("value")

回答4:

After click reply button, use .visibility_of_element_located like bellow:

browser.find_element_by_css_selector(".reply-button").click()

#wait initialize, in seconds
wait = WebDriverWait(browser, 10)

email = wait.until(EC.visibility_of_element_located((By.CSS_SELECTOR, '.anonemail'))).get_attribute("value")
print(email)

Following import:

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

Waits docs

来源：https://stackoverflow.com/questions/59130200/selenium-wait-until-element-is-present-visible-and-interactable

标签

python

selenium

selenium-webdriver

webdriverwait

expected-condition