infinite scroll of stackstatus with python in phantomjs

infiniteScroll_1.py

import selenium
import time
from selenium import webdriver

browser = webdriver.PhantomJS("phantomjs")
browser.get("https://twitter.com/StackStatus")
print browser.title

pause = 3

lastHeight = browser.execute_script("return document.body.scrollHeight")
print lastHeight
i = 0
browser.get_screenshot_as_file("test03_1_"+str(i)+".jpg")
while True:
	browser.execute_script("window.scrollTo(0, document.body.scrollHeight);")
	time.sleep(pause)
	newHeight = browser.execute_script("return document.body.scrollHeight")
	print newHeight
	if newHeight == lastHeight:
		break
	lastHeight = newHeight
	i += 1
	browser.get_screenshot_as_file("test03_1_"+str(i)+".jpg")

browser.quit()

infiniteScroll_2.py

import selenium
import time
from selenium import webdriver
from selenium.webdriver.support.ui import WebDriverWait
import selenium.webdriver.support.expected_conditions as EC
from selenium.webdriver.common.by import By

browser = webdriver.PhantomJS("phantomjs")
#browser.get("https://twitter.com/StackStatus")
browser.get("https://twitter.com/StackOverheards") # shorter, so that ending can be tested
print browser.title

i = 0
browser.get_screenshot_as_file("test03_2_"+str(i)+".jpg")
while True:
	print "i", i
	elemsCount = browser.execute_script("return document.querySelectorAll('.stream-items > li.stream-item').length")
	#print "c", elemsCount
	
	browser.execute_script("window.scrollTo(0, document.body.scrollHeight);")
	
	#element = WebDriverWait(browser, 20).until(
	#	EC.presence_of_element_located((By.XPATH, 
	#		"//*[contains(@class,'GridTimeline-items')]/li[contains(@class,'stream-item')]["+str(elemsCount+1)+"]")))
	try:
		WebDriverWait(browser, 20).until(
			lambda x: x.find_element_by_xpath(
				"//*[contains(@class,'stream-items')]/li[contains(@class,'stream-item')]["+str(elemsCount+1)+"]"))
	except:
		break
	
	i += 1
	browser.get_screenshot_as_file("test03_2_"+str(i)+".jpg")

browser.quit()

why not user-agent?