temp.py

#!/usr/bin/env python3

import requests
from lxml import html

def login(name,password):
    url='http://passport.cnblogs.com/login.aspx'
    session = requests.session()
    ua = 'Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/36.0.1985.125 Safari/537.36'
    session.headers.update({'User-Agent': ua})
    login_page_request = session.get(url)
    tree = html.fromstring(login_page_request.text)
    viewstate = tree.xpath('//*[@id="__VIEWSTATE"]/@value')[0]
    eventvalidation = tree.xpath('//input[@id="__EVENTVALIDATION"]/@value')[0]

    post_data = { 
                    '__VIEWSTATE': viewstate,
                    '__EVENTVALIDATION': eventvalidation,
                    'tbUserName': name,
                    'tbPassword': password,
                    'btnLogin': '登  录',
                    'txtReturnUrl': 'http://home.cnblogs.com/'
                }   
    login_post_request = session.post(url, data=post_data)
    print(login_post_request)
    print(login_post_request.url)
    print(login_post_request.status_code)
    print(login_post_request.history)
    print(login_post_request.text)

if __name__ == '__main__':
    name=input('请输入账号')
    password=input('请输入密码')
    login(name,password)