Webdriver (python)中调用JS

  1、Webdriver 中调用JS，由于页面中的input是被隐藏起来的，所以必须用JS把隐藏的元素显示出来；

       browser.find_element_by_xpath("//div[@id='surveyItemsWrap']/div/div[2]/button[2]").click()
        time.sleep(5)
        inputs=browser.find_element_by_xpath("//body/input")
        js="var q=document.getElementByClassName('ts_bg alert');q.style.display='block';"
        #  setAttribute("style","display:block     
        print "js"
        browser.execute_script(js)
        browser.find_element_by_xpath("//body/input").send_keys('F:\Img2.jpg')
        print "ok"

报错：

Traceback (most recent call last):
  File "E:eclipsePythonCasesrcSurvey_testLogicMore.py", line 85, in test_Surveyor
    browser.execute_script(js)
  File "D:Python27libsite-packagesseleniumwebdriver
emotewebdriver.py", line 396, in execute_script
    {'script': script, 'args':converted_args})['value']
  File "D:Python27libsite-packagesseleniumwebdriver
emotewebdriver.py", line 164, in execute
    self.error_handler.check_response(response)
  File "D:Python27libsite-packagesseleniumwebdriver
emoteerrorhandler.py", line 164, in check_response
    raise exception_class(message, screen, stacktrace)
WebDriverException: Message: u"unknown error: Object #<HTMLDocument> has no method 'getElementByClassName'
  (Session info: chrome=28.0.1500.72)
  (Driver info: chromedriver=2.3,platform=Windows NT 6.1 SP1 x86_64)" 

PS: JS有待加深学习！