Selenium/Chromedriver hangs on a new tab containing an alert

Phani Vadrevu

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Jun 1, 2017, 8:46:39 PM6/1/17

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Hi,

I have a minimal example for which Chromedriver seems to hang. Here's the sample HTML pages:

alert.html:

<html>
        <body>
            <a href="test_alert.html" target="_blank" id="test">Visit Alert test!</a>
        </body>
</html>

test_alert.html:

<html>
    <script type="text/javascript">
        alert("Hello world");
    </script>
</html>

Below is the driver Python script for this:

from selenium import webdriver
import time

SHORT_PAUSE = 5
capabilities = {'chrome.binary': '/usr/bin/google-chrome'}
driver = webdriver.Remote('http://localhost:9515', capabilities)
url = "http://localhost:8888/alert.html"
driver.get(url)
time.sleep(SHORT_PAUSE)

element = driver.find_element_by_id("test")
element.click()
print "done clicking"

# Usually prints something like: "[u'CDwindow-XXXX', u'CDwindow-YYYY']" 
print driver.window_handles
time.sleep(SHORT_PAUSE)
driver.switch_to.window(driver.window_handles[1])

# Selenium is unresponsive after this and 
# never prints the below line
print "current url:", driver.current_url
alert = driver.switch_to.alert
print "switched to alert. Text:", alert.text
alert.accept()
print "Accepted modal dialog...."

Version information:

Python: 2.7.6
Selenium: 3.4.2
Chrome driver: 2.29
Chrome: 58.0.3029.110
OS: Ubuntu 14.04.5 LTS an

Please let me know if you need anymore information. I am trying to build a web crawler using Selenium and I have to deal with plenty of such pages. I would appreciate any advice you might have regarding this.

Thanks,

Phani

darrell grainger

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Jun 2, 2017, 9:35:28 AM6/2/17

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This is a tough one. When you click the link on the alert.html it will open a new window but then IMMEDIATELY this new window will open an alert. I believe once the alert is open you are losing control in Selenium. You cannot switch to the alert before you open the new window because the alert does not exist. The moment you click the link on the main window, it opens a new window and focus goes to the new alert. I think at that point you need something outside of Selenium to find and click the alert

Essentially, you cannot dismiss or accept the alert until you switch to the new window but you cannot switch to the new window because there is an alert present. Looks like you found something you cannot do with Selenium alone.

thi...@thoughtworks.com

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Jun 5, 2017, 3:06:04 AM6/5/17

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The problem is with switching to window..Verify if you are switching to correct window. Verify if driver is passed to this window context...Usually switching to windows take time.Add a sleep for switch to happen and then click on the alert.

SuperKevy

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Jun 5, 2017, 8:32:32 PM6/5/17

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The html in test_alert.html is not compliant to the best of my knowledge.

Try the same script within the body. Do you get the same blocking code condition?

<html>

<body>

alert("Hello world");

</script>

</body>

</html>

darrell grainger

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Jun 6, 2017, 8:07:40 AM6/6/17

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I didn't use Phani's HTML. I had my IDE generate HTML5 compliant versions of the HTML and it still failed. I think the problem is that clicking the link on the first HTML page opens the second page and launches the alert right away. Selenium is still watching the first page. When you navigate to the second page, it does not see the alert because the alert was already present. It feels like Selenium wants to switch to the other page and interact with it somehow but it cannot because there is an alert present.

Darrell