How does python + selenium + chrome operate the scroll bar

1. background

• When using selenium to simulate browser, you often need to pull down scroll bar, generally for two purposes:
  
  • Anthropomorphic operation, breaking through the sophisticated anti climbing system.
  • Some elements don't load out normally. You need to drag the drop-down bar to load out slowly. It's similar to Taobao.

2. environment

• python 3.6.1
• System: win7
• IDE: pycharm
• Installed chrome browser
• Configure the chrome driver
• selenium 3.7.0

3. Operation method

3.1. Drag to the specified element location.

from selenium import webdriver
from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.common.action_chains import ActionChains
from selenium.webdriver.common.keys import Keys
from selenium.webdriver.support.ui import Select

import time
import random

# Load the xpath plug-in
chrome_options = webdriver.ChromeOptions()
extension_path = 'D:/extension/XPath-Helper_v2.0.2.crx'
chrome_options.add_extension(extension_path)

browser = webdriver.Chrome(chrome_options=chrome_options)
#browser.maximize_window()
wait = WebDriverWait(browser, 25)
waitPopWindow = WebDriverWait(browser, 25)

browser.get("https://www.amazon.com/s/ref=nb_sb_noss_2?url=search-alias%3Daps&field-keywords=phone")

time.sleep(random.randrange(5, 10, 1))

# Find the Next Page button, which belongs to the visible element
# There are two ways to write js code, but the requirements for elements are different, and focus is more strict

# The first method: focus
targetElem = browser.find_element_by_xpath("//a[@id='pagnNextLink']")
browser.execute_script("arguments[0].focus();", targetElem)

# The second method: scrollIntoView
# targetElem = browser.find_element_by_xpath("//a[@id='pagnNextLink']/span[@id='pagnNextString']")
# browser.execute_script("arguments[0].scrollIntoView();", targetElem)    # Drag to visible element

print(f"End drag scroll bar....")
time.sleep(random.randrange(5, 10, 1))
browser.quit()

3.2. Specify the pull-down distance

from selenium import webdriver
from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.common.action_chains import ActionChains
from selenium.webdriver.common.keys import Keys
from selenium.webdriver.support.ui import Select

import time
import random

# Load the xpath plug-in
chrome_options = webdriver.ChromeOptions()
extension_path = 'D:/extension/XPath-Helper_v2.0.2.crx'
chrome_options.add_extension(extension_path)

browser = webdriver.Chrome(chrome_options=chrome_options)
browser.maximize_window()
wait = WebDriverWait(browser, 25)
waitPopWindow = WebDriverWait(browser, 25)

browser.get("https://www.amazon.com/s/ref=nb_sb_noss_2?url=search-alias%3Daps&field-keywords=phone")

time.sleep(random.randrange(5, 10, 1))
# Specified pixels
jsCode = "var q=document.documentElement.scrollTop=100000"
browser.execute_script(jsCode)
print("Drag slider to bottom...")

time.sleep(random.randrange(5, 10, 1))
browser.quit()

3.3. Send tab key, move to target element

• You can send the tab key to switch the page buttons, so as to pull down the scroll bar. But it must be noted that the specified elements must be able to be selected by tab key, such as input box, hyperlink, Button, etc.

from selenium import webdriver
from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.common.action_chains import ActionChains
from selenium.webdriver.common.keys import Keys
from selenium.webdriver.support.ui import Select

import time
import random

# Load the xpath plug-in
chrome_options = webdriver.ChromeOptions()
extension_path = 'D:/extension/XPath-Helper_v2.0.2.crx'
chrome_options.add_extension(extension_path)

browser = webdriver.Chrome(chrome_options=chrome_options)
browser.maximize_window()
wait = WebDriverWait(browser, 25)
waitPopWindow = WebDriverWait(browser, 25)

browser.get("https://www.amazon.com/s/ref=nb_sb_noss_2?url=search-alias%3Daps&field-keywords=phone")

time.sleep(random.randrange(5, 10, 1))

# Find the Next Page button, which belongs to the visible element

# Specifies that the element is a hyperlink -- you can use the Tab key to switch to
targetElem = browser.find_element_by_xpath("//a[@id='pagnNextLink']")

# This element is not a hyperlink, so the Tab key cannot be received
# targetElem = browser.find_element_by_xpath("//a[@id='pagnNextLink']/span[@id='pagnNextString']")

targetElem.send_keys(Keys.TAB)

print(f"End drag scroll bar....")
time.sleep(random.randrange(5, 10, 1))
browser.quit()