python - Getting "Message: h is null" -

i've encountered i've never seen before while using selenium.

the code (quite simple , straightforward):

from selenium import webdriver  driver = webdriver.firefox() driver.get("http://www.drugs.com/drug-class/laxatives.html?condition_id=&generic=0&sort=rating&order=desc")   print driver.find_element_by_tag_name("title").text 

here stack trace of error i'm getting:

traceback (most recent call last):   file "/users/a/p/so/selenium_scripts/test.py", line 6, in <module>     print driver.find_element_by_tag_name("title").text   file "/users/a/.virtualenvs/so/lib/python2.7/site-packages/selenium/webdriver/remote/webdriver.py", line 328, in find_element_by_tag_name     return self.find_element(by=by.tag_name, value=name)   file "/users/a/.virtualenvs/so/lib/python2.7/site-packages/selenium/webdriver/remote/webdriver.py", line 664, in find_element     {'using': by, 'value': value})['value']   file "/users/a/.virtualenvs/so/lib/python2.7/site-packages/selenium/webdriver/remote/webdriver.py", line 175, in execute     self.error_handler.check_response(response)   file "/users/a/.virtualenvs/so/lib/python2.7/site-packages/selenium/webdriver/remote/errorhandler.py", line 166, in check_response     raise exception_class(message, screen, stacktrace) selenium.common.exceptions.webdriverexception: message: h null 

using firefox 37.0 , selenium 2.45.0.

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observations:

• if switch webdriver.chrome() - don't see errors
• if use different url, e.g. https://google.com - don't see errors

• i've tried explicitly wait search results visible before making further actions, still same error, code i've used:

  from selenium import webdriver selenium.webdriver.common.by import selenium.webdriver.support.ui import webdriverwait selenium.webdriver.support import expected_conditions ec  driver = webdriver.firefox() driver.get("http://www.drugs.com/drug-class/laxatives.html?condition_id=&generic=0&sort=rating&order=desc")   # wait table list load webdriverwait(driver, 10).until(ec.presence_of_element_located((by.css_selector, "table.data-list"))) 

• it not googleable means web-site specific, but, noted before, no errors in chrome

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where error coming , can prevent/fix it? mean cannot browser/locate elements on particular web page using selenium+firefox?

looks selenium 2.45.0 not support ff 37.

the change log shows selenium 2.44 supported ff33. selenium 2.45 released around feb 26th 2015, while ff37 released on march 31st 2015.