introducing selenium related By, Keys, WebDriverWait, ActionChains, display wait wait implicit

# -*- coding: utf-8 -*-
"""
@author: Dell Created on Tue Dec 24 12:33:56 2019
"""
import time
from selenium import webdriver
from selenium.webdriver.support.ui import WebDriverWait#等待一个元素加载完成
from selenium.webdriver.support import expected_conditions as EC

from selenium.webdriver.common.by import By
from selenium.webdriver.common.keys import Keys#键盘
from selenium.webdriver.common.action_chains import ActionChains#鼠标


driver= webdriver.Chrome()
driver.get("http://www.baidu.com")

driver.implicitly_wait(10)#控制操作的时间在10s以内，隐式等待，很少用

# driver.find_element_by_id("kw").send_keys("selenium")

#打开一个网页，15s超时，每0.5s检测一次，直到id为kw的元素出现，
#节约时间，显示等待15s，必须等待这个元素出现，若15s之后还没出现才会不等待了
WebDriverWait(driver, 15, 0.5).until(EC.presence_of_element_located((By.ID,"kw"))).send_keys("selenium")#
driver.find_element_by_id("su").click()#点击百度一下进行搜索

nums_span = driver.find_element_by_class_name("nums_text")
if nums_span.is_displayed():#判断这个元素是否已经显示出来
    print(nums_span.text)


time.sleep(5)
driver.close()





if __name__ == "__main__":
    
    pass