title: Selenium prints empty innerHTML/innerText of an element
body: <p>With Selenium, why does the following function print empty string? Same if I try <code>'innerText'</code> instead of <code>'innerHTML'</code>.</p>
  
  <p><code>send_keys</code> part works fine though.</p>
  
  <pre><code>def button_clicked(self):
          browser = webdriver.Firefox()
          browser.get('https://www.google.com')
          search_box = browser.find_element_by_xpath("//input[@title='Search']")
          search_box_HTML = search_box.get_attribute('innerHTML')
          print(search_box_HTML)
  </code></pre>