import asyncio
from pyppeteer import launch
from lxml import etree

async def main():
    bro=await launch(headless=False)
    page=await bro.newPage()
    await page.goto('http://quotes.toscrape.com/')
    page_text=await page.content()
    return page_text
def parse(tasks):
    page_text=tasks.result()
    tree=etree.HTML(page_text)
    div_list=tree.xpath('/html/body/div/div[2]/div[1]/div')
    for element in div_list:
        content=element.xpath('.//span/text()')
        print(content)

c=main()
tasks=asyncio.ensure_future(c)
tasks.add_done_callback(parse)
loop=asyncio.get_event_loop()
loop.run_until_complete(tasks)

pyppteer用于抓取网页中动态加载的内容，也可以用于模拟登陆