detect new element in html using selenium, python

Question

is it possible to detect in selenium, that new dynamic element added in html

msg_box = driver.find_element_by_class_name('_3u328')
 msg_box.send_keys('---')
 button = driver.find_element_by_class_name('_3M-N-')
 button.click()

Answer 1

If you know what element will be added you can use explicit wait with :

from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as ec
is_found = WebDriverWait(webdriver, time).until(ec.presence_of_element_located((by, locator)))

Small info on waits can be found here

Answer 2

You can find (in a loop) all elements which match your condition with find_elements_by_* getting the list of elements and check if the list is changed. If yes - that would mean new element was added.

Comparing previous list and new one you will detect which element exactly.