How do I use the HTMLUnit driver with Selenium from Python?


How do I tell Selenium to use HTMLUnit?

I'm running selenium-server-standalone-2.0b1.jar as a Selenium server in the background, and the latest Python bindings installed with "pip install -U selenium".

Everything works fine with Firefox. But I'd like to use HTMLUnit, as it is lighter weight and doesn't need X. This is my attempt to do so:

>>> import selenium
>>> s = selenium.selenium("localhost", 4444, "*htmlunit", "http://localhost/")
>>> s.start()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python2.6/dist-packages/selenium/selenium/", line 189, in start
    result = self.get_string("getNewBrowserSession", start_args)
  File "/usr/local/lib/python2.6/dist-packages/selenium/selenium/", line 223, in get_string
    result = self.do_command(verb, args)
  File "/usr/local/lib/python2.6/dist-packages/selenium/selenium/", line 217, in do_command
    raise Exception, data
Exception: Failed to start new browser session: Browser not supported: *htmlunit

Supported browsers include:

So the question is, what is the HTMLUnit driver called? How do I enable it?

The code for HTMLUnit seems to be in the source for Selenium 2, so I expected it to be available by default like the other browsers. I can't find any instructions on how to enable it.

1/6/2011 6:29:37 PM

Accepted Answer

using the selenium 2.20.0.jar server and matching python version, I am able to use HtmlUnitDriver by specifying the browser as *mock

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

server_url = "http://%s:%s/wd/hub" % (test_host, test_port)
dc = DesiredCapabilities.HTMLUNIT
wd = webdriver.Remote(server_url, dc)
3/9/2016 4:35:18 PM

As of the 2.0b3 release of the python client you can create an HTMLUnit webdriver via a remote connection like so:

from selenium import webdriver
driver = webdriver.Remote(

You can also use the HTMLUNITWITHJS capability item for a browser with Javascript support.

Note that you need to run the Selenium Java server for this to work, since HTMLUnit is implemented on the Java side.

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