Python Selenium Scroll Down

from selenium import webdriver
import time

# open firefox
browser = webdriver.Firefox()          
browser.get("https://www.google.com.tr/")     
time.sleep(1)                       

# search input field
search = browser.find_element_by_xpath("//*[@id='tsf']/div[2]/div/div[1]/div/div[1]/input") 
search.send_keys("javascript")
time.sleep(1)                       

# search button
search_button = browser.find_element_by_xpath("//*[@id='tsf']/div[2]/div/div[2]/div[2]/div[2]/center/input[1]")
search_button.submit()
time.sleep(3)                       

# scroll
scrollCounter = 0
while scrollCounter <= 5:
    browser.execute_script("window.scrollTo(0, document.body.scrollHeight);")
    scrollCounter += 1
    time.sleep(1)

# close firefox
browser.close()