Don't Wait for a Page to Load Using Selenium in Python

Don't wait for a page to load using Selenium in Python

ChromeDriver 77.0 (which supports Chrome version 77) now supports eager as pageLoadStrategy.

Resolved issue 1902: Support eager page load strategy [Pri-2]

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As you question mentions of click on elements and scrape data before the page has fully loaded in this case we can take help of an attribute pageLoadStrategy. When Selenium loads a page/url by default it follows a default configuration with pageLoadStrategy set to normal. Selenium can start executing the next line of code from different Document readiness state. Currently Selenium supports 3 different Document readiness state which we can configure through the pageLoadStrategy as follows:

1. none (undefined)
2. eager (page becomes interactive)
3. normal (complete page load)

Here is the code block to configure the pageLoadStrategy:

from selenium import webdriver
from selenium.webdriver.common.desired_capabilities import DesiredCapabilities

binary = r'C:\Program Files\Mozilla Firefox\firefox.exe'
caps = DesiredCapabilities().FIREFOX
# caps["pageLoadStrategy"] = "normal"  #  complete
caps["pageLoadStrategy"] = "eager"  #  interactive
# caps["pageLoadStrategy"] = "none"   #  undefined
driver = webdriver.Firefox(capabilities=caps, firefox_binary=binary, executable_path="C:\\Utility\\BrowserDrivers\\geckodriver.exe")
driver.get("https://google.com")

How to make Selenium not wait till full page load, which has a slow script?

When Selenium loads a page/url by default it follows a default configuration with pageLoadStrategy set to normal. To make Selenium not to wait for full page load we can configure the pageLoadStrategy. pageLoadStrategy supports 3 different values as follows:

1. normal (full page load)
2. eager (interactive)
3. none

Here is the code block to configure the pageLoadStrategy :

• Firefox :

  from selenium import webdriver
  from selenium.webdriver.common.desired_capabilities import DesiredCapabilities
  
  caps = DesiredCapabilities().FIREFOX
  caps["pageLoadStrategy"] = "normal"  #  complete
  #caps["pageLoadStrategy"] = "eager"  #  interactive
  #caps["pageLoadStrategy"] = "none"
  driver = webdriver.Firefox(desired_capabilities=caps, executable_path=r'C:\path\to\geckodriver.exe')
  driver.get("http://google.com")
  

• Chrome :

  from selenium import webdriver
  from selenium.webdriver.common.desired_capabilities import DesiredCapabilities
  
  caps = DesiredCapabilities().CHROME
  caps["pageLoadStrategy"] = "normal"  #  complete
  #caps["pageLoadStrategy"] = "eager"  #  interactive
  #caps["pageLoadStrategy"] = "none"
  driver = webdriver.Chrome(desired_capabilities=caps, executable_path=r'C:\path\to\chromedriver.exe')
  driver.get("http://google.com")
  

Note : pageLoadStrategy values normal, eager and none is a requirement as per WebDriver W3C Editor's Draft but pageLoadStrategy value as eager is still a WIP (Work In Progress) within ChromeDriver implementation. You can find a detailed discussion in “Eager” Page Load Strategy workaround for Chromedriver Selenium in Python

Wait until page is loaded with Selenium WebDriver for Python

The webdriver will wait for a page to load by default via .get() method.

As you may be looking for some specific element as @user227215 said, you should use WebDriverWait to wait for an element located in your page:

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

browser = webdriver.Firefox()
browser.get("url")
delay = 3 # seconds
try:
    myElem = WebDriverWait(browser, delay).until(EC.presence_of_element_located((By.ID, 'IdOfMyElement')))
    print "Page is ready!"
except TimeoutException:
    print "Loading took too much time!"

I have used it for checking alerts. You can use any other type methods to find the locator.

EDIT 1:

I should mention that the webdriver will wait for a page to load by default. It does not wait for loading inside frames or for ajax requests. It means when you use .get('url'), your browser will wait until the page is completely loaded and then go to the next command in the code. But when you are posting an ajax request, webdriver does not wait and it's your responsibility to wait an appropriate amount of time for the page or a part of page to load; so there is a module named expected_conditions.

python selenium: does not wait until page is loaded after a click() command

Fundamentally if the page is being generated by JavaScript then there is no way to tell when it has "finished" loading.

However. I typically try to retrieve a page element, catch the exception and keep on trying until a timeout is reached. I might also check that the element is visible not merely present.

There must be some DOM element whose visibility you can use to test that a page has "finished" loading. I typically have a wait_for_element_visibility, and wait_for_element_presence functions in my test cases.

def wait_for_visibility(self, selector, timeout_seconds=10):
    retries = timeout_seconds
    while retries:
        try:
            element = self.get_via_css(selector)
            if element.is_displayed():
                return element
        except (exceptions.NoSuchElementException,
                exceptions.StaleElementReferenceException):
            if retries <= 0:
                raise
            else:
                pass

        retries = retries - 1
        time.sleep(pause_interval)
    raise exceptions.ElementNotVisibleException(
        "Element %s not visible despite waiting for %s seconds" % (
            selector, timeout_seconds)
    )

get_via_css is one of my own functions but I hope it's fairly clear what it is doing.

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