實(shí)例：百度搜索，結(jié)果列表翻頁(yè)查詢
　　解決問(wèn)題：解決selenium driver獲取web頁(yè)面元素時(shí)，元素過(guò)期問(wèn)題
　　思路1：獲取所有“頁(yè)面翻頁(yè)鏈接”元素，然后遍歷元素并點(diǎn)擊
# -*- coding: utf-8 -*-
from selenium import webdriver
import time
if __name__ == "__main__":
driver = webdriver.Firefox()
driver.maximize_window()
driver.get('http://www.baidu.com')
driver.implicitly_wait(5)
driver.find_element_by_id('kw1').send_keys('selenium')
driver.find_element_by_id('su1').click()
page = driver.find_element_by_id('page')
pages = page.find_elements_by_tag_name('a')  #查找所有翻頁(yè)跳轉(zhuǎn)鏈接
#設(shè)置滾動(dòng)條位置為底部
js = 'document.documentElement.scrollTop=10000'
for each in pages:
driver.execute_script(js)   #拖動(dòng)滾動(dòng)條到底部
each.click()
driver.execute_script(js)
time.sleep(3)
driver.quit()
　　結(jié)果：點(diǎn)擊第3頁(yè)時(shí)，程序出錯(cuò)
　　selenium.common.exceptions.StaleElementReferenceException: Message: u'Element not found in the cache - perhaps the page has changed since it was looked up' ; Stacktrace:
　　即在cache中找不到元素，可能是在元素被找到之后頁(yè)面變換了。 這說(shuō)明，當(dāng)前頁(yè)面發(fā)生跳轉(zhuǎn)之后，存在cache中的與這個(gè)頁(yè)面相關(guān)的元素也被清空了
　　思路2：基于思路1的錯(cuò)誤結(jié)果分析>先獲取每個(gè)頁(yè)面數(shù)，然后每次點(diǎn)擊某個(gè)頁(yè)面，跳轉(zhuǎn)后重新獲取下一個(gè)頁(yè)面翻頁(yè)鏈接，然后點(diǎn)擊，循環(huán)。。
# -*- coding: utf-8 -*-
from selenium import webdriver
import time
if __name__ == "__main__":
driver = webdriver.Firefox()
driver.maximize_window()
driver.get('http://www.baidu.com')
driver.implicitly_wait(5)
driver.find_element_by_id('kw1').send_keys('selenium')
driver.find_element_by_id('su1').click()
page = driver.find_element_by_id('page')
pages = page.find_elements_by_tag_name('a')
js = 'document.documentElement.scrollTop=10000'
total = len(pages)
has_pre_page = False
page_num = 0
for i in range(total):
driver.execute_script(js)
pn=10
page_num = page_num + 1 #設(shè)置頁(yè)面號(hào)
one_page = driver.find_element_by_css_selector('p[id="page"]>a:nth-of-type('+str(page_num)+')')
one_page.click()