python+selenium selenium.webdriver.common.by之By

By是selenium中内置的一个class，在这个class中有各种方法来定位元素

By所支持的定位器的分类：

CLASS_NAME = 'class name'
CSS_SELECTOR = 'css selector'
ID = 'id'
LINK_TEXT = 'link text'
NAME = 'name'
PARTIAL_LINK_TEXT = 'partial link text'
TAG_NAME = 'tag name'
XPATH = 'xpath'

用法

from selenium.webdriver.common.by import By
username_loc=(By.ID, "idInput")
password_loc=(By.ID, "pwdInput")
submit_loc=(By.ID, "loginBtn")