Waiting in Selenium

Introduction#

One of the most common stumbling blocks for newer Selenium users is waiting until a page is fully loaded. Human users can easily tell if a page has fully loaded or if it is still loading. Selenium, however, just waits for a set amount of time. Therefore, it is often convenient to have a good way to wait for elements in a page. While it is possible to do this with a loop and sleep() functions, there are much cleaner ways already built into Selenium.

Explicit Wait in Python

When browser navigates to a dynamic page (most commonly AJAX-based web application), the elements on the page can take different time to load, and furthermore: some elements will only load in response to some user actions. In such cases direct retrieval of an element may fail:

# Don't do this: may fail on dynamic page with ElementNotVisibleException
element = driver.find_element_by_name('q')

The most obvious solution it seems to introduce the wait before retrieving elements:

# Don't do this: inefficient solution for ElementNotVisibleException 
time.sleep(5) # delays for 5 seconds  
element = driver.find_element_by_name('q')

But such solution is inefficient, since it causes the test to always wait for 5 seconds, even when the element in most cases appears after 1 second (and only sometimes requires up to 5 seconds). It doesn’t look much if it’s one place, but usually each test deals with multiple elements, and there are multiple tests, which adds up to overall test duration.

A better solution is to wait for element to appear for up to 5 seconds, but return from the wait as soon as element is found. WebDriverWait allows you to do just that.

The following example navigates to www.google.com, waits (for up to 5 seconds) for the search bar to load, and then searches for “selenium”.

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

# Create a new chromedriver instance
driver = webdriver.Chrome()

# Go to www.google.com
driver.get("https://www.google.com")

try:
    # Wait as long as required, or maximum of 5 sec for element to appear
    # If successful, retrieves the element
    element = WebDriverWait(driver,5).until(
         EC.presence_of_element_located((By.NAME, "q")))

    # Type "selenium"
    element.send_keys("selenium")
    
    #Type Enter
    element.send_keys(Keys.ENTER)

except TimeoutException:
    print("Failed to load search bar at www.google.com")
finally:
    driver.quit()

Wait in Java with selenium

Explicit wait : Wait for a certain condition to occur before proceeding further in the code.

WebDriver driver = new FirefoxDriver();
driver.get("https://google.com");
WebElement myElement = (new WebDriverWait(driver, 10))
  .until(ExpectedConditions.presenceOfElementLocated(By.id("myElement")));

Implicit wait: Wait for a certain amount of time when trying to find an element or elements if they are not immediately available.

WebDriver driver = new FirefoxDriver();
driver.manage().timeouts().implicitlyWait(10, TimeUnit.SECONDS);
driver.get("https://google.com");
WebElement myElement = driver.findElement(By.id("myElement"));