title: Selenium in Python: Nothing returned after sending in keys and selecting an option
body: <p>I am building up a web scraper for this website: <a href="http://app1.sfda.gov.cn/datasearchcnda/face3/base.jsp?tableId=25&amp;tableName=TABLE25&amp;title=%E4%B8%AD%E8%8D%AF&amp;bcId=152904713761213296322795806604" rel="nofollow noreferrer">Link</a>. Instead of scraping off all the content, I only need some of them, and that is why I add some search conditions in the "快速查询" form. </p>
  
  <p>The website puts all the key content in JavaScript... Not sure if this is the reason. </p>
  
  <pre class="lang-py prettyprint-override"><code>driver.get('http://app1.sfda.gov.cn/datasearchcnda/face3/base.jsp?tableId=25&amp;tableName=TABLE25&amp;title=%E4%B8%AD%E8%8D%AF&amp;bcId=152904713761213296322795806604')
  
  s1 = Select(driver.find_element_by_id('s31p0'))
  s1.select_by_value('25,152904756797819090327732889259') #the option is 中药
  print (s1.first_selected_option.text)
  
  elem = driver.find_element_by_id('keyword')
  elem.send_keys('注射' + Keys.ENTER) #the key word is 注射
  
  soup = BeautifulSoup(driver.page_source, 'lxml')
  js_links = soup.select('a[href^="javascript:"]') #find all the links
  print(js_links)
  </code></pre>
  
  <p>Normally, it should return a list of 15  tags like this:
  6.龟鹿补肾片 (86903249000087 郑州福瑞堂制药有限公司 国药准字Z20090420)</p>
  
  <p>But after adding all the conditions, it only returns "[]". </p>
  
  <p>Can anyone tell me how should I fix it? Thanks in advance!</p>