Wait For Page Load in Selenium

Selenium how to manage wait for page load?

To wait for document.readyState to be complete isn't a full proof approach to ensure presence, visibility or interactibility of an element.

Hence, the function:

JavascriptExecutor js = (JavascriptExecutor) driver.getWebDriver();
String result = js.executeScript("return document.readyState").toString();
    if (!result.equals("complete")) {
     Thread.sleep(1000)
    } 
}

And even waiting for jQuery.active == 0:

public void WaitForAjax2Complete() throws InterruptedException
{
    while (true)
    {
        if ((Boolean) ((JavascriptExecutor)driver).executeScript("return jQuery.active == 0")){
            break;
    }
    Thread.sleep(100);
    }
}

Will be a pure overhead.

You can find a couple of relevant discussions in:

Selenium IE WebDriver only works while debugging
Do we have any generic function to check if page has completely loaded in Selenium

Solution

The effective approach will be to induce WebDriverWait inconjunction with the ExpectedConditions either for:

presence of element
visibility of element
interactibility of element

You can find a couple of relevant discussions in:

Selenium: How selenium identifies elements visible or not? Is is possible that it is loaded in DOM but not rendered on UI?
WebDriverWait not working as expected

More than one thread to crawl

WebDriver is not thread-safe. Having said that, if you can serialise access to the underlying driver instance, you can share a reference in more than one thread. This is not advisable. But you can always instantiate one WebDriver instance for each thread.

Ideally the issue of thread-safety isn't in your code but in the actual browser bindings. They all assume there will only be one command at a time (e.g. like a real user). But on the other hand you can always instantiate one WebDriver instance for each thread which will launch multiple browsing tabs/windows. Till this point it seems your program is perfect.

Now, different threads can be run on same Webdriver, but then the results of the tests would not be what you expect. The reason behind is, when you use multi-threading to run different tests on different tabs/windows a little bit of thread safety coding is required or else the actions you will perform like click() or send_keys() will go to the opened tab/window that is currently having the focus regardless of the thread you expect to be running. Which essentially means all the test will run simultaneously on the same tab/window that has focus but not on the intended tab/window.

Selenium page loading wait methods

There are two different concepts here. The first is that with w3c you can now set a Page Load Strategy in the capabilities at the beginning of a session. This affects what Document readiness state the driver will wait for before returning control to the user. If the specified readiness state is not satisfied before the page load timeout, the driver is supposed to return an error.

Note that both of these things only apply to navigation events, so clicking an element that results in a page load should not trigger these.

To complicate things one more level, Chromedriver has an open bug for incorrectly:

wait[ing] for navigation to complete at the end of almost all commands

So for right now Chrome tests actually will wait for the specified document readiness state on clicks.

Finally, remember that for today's web there is typically a lot of content loaded dynamically via JavaScript, so even when the document readiness state is "complete" the DOM is unlikely to be in it's final state, which is why you are encouraged to use explicit waits for the things you actually want to interact with.

How can I wait for page load in selenium before moving to another page? (C#)

bool wait = new WebDriverWait(Driver, TimeSpan.FromSeconds(60)).Until(d => ((IJavaScriptExecutor)d).ExecuteScript("return document.readyState").Equals("complete")); 

if(wait == true)
{
    //Your code
}

Above code will wait for page to load for 60 seconds and return true if page is ready(within 60 seconds), false if page is not ready (after 60 seconds).

Selenium WebDriver: Wait for complex page with JavaScript to load

If anyone actually knew a general and always-applicable answer, it would have been implemented everywhere ages ago and would make our lives SO much easier.

There are many things you can do, but every single one of them has a problem:

As Ashwin Prabhu said, if you know the script well, you can observe its behaviour and track some of its variables on window or document etc. This solution, however, is not for everyone and can be used only by you and only on a limited set of pages.
Your solution by observing the HTML code and whether it has or hasn't been changed for some time is not bad (also, there is a method to get the original and not-edited HTML directly by WebDriver), but:
- It takes a long time to actually assert a page and could prolong the test significantly.
- You never know what the right interval is. The script might be downloading something big that takes more than 500 ms. There are several scripts on our company's internal page that take several seconds in IE. Your computer may be temporarily short on resources - say that an antivirus will make your CPU work fully, then 500 ms may be too short even for a noncomplex scripts.
- Some scripts are never done. They call themselves with some delay (setTimeout()) and work again and again and could possibly change the HTML every time they run. Seriously, every "Web 2.0" page does it. Even Stack Overflow. You could overwrite the most common methods used and consider the scripts that use them as completed, but ... you can't be sure.
- What if the script does something other than changing the HTML? It could do thousands of things, not just some innerHTML fun.
There are tools to help you on this. Namely Progress Listeners together with nsIWebProgressListener and some others. The browser support for this, however, is horrible. Firefox began to try to support it from FF4 onwards (still evolving), IE has basic support in IE9.

And I guess I could come up with another flawed solution soon. The fact is - there's no definite answer on when to say "now the page is complete" because of the everlasting scripts doing their work. Pick the one that serves you best, but beware of its shortcomings.

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.