<input id="qcreatetask" class="placeholder-italic" placeholder="提交">
from selenium import webdriver
from selenium.webdriver.common.by import By
driver = webdriver.Chrome()
driver.get("https://www.***.cn")
#通过ID定位
driver.find_element(By.ID,"qcreatetask")
#通过CSS定位
driver.find_element(By.CSS_SELECTOR,"#qcreatetask")
#通过CSS属性定位
driver.find_element(By.CSS_SELECTOR,"#qcreatetask[class='placeholder-italic']")
#CSS定位,属性值由多个空格隔开,匹配其中一个值的方法
driver.find_element(By.CSS_SELECTOR,"#qcreatetask[class~='placeholder-italic']")
#CSS定位,匹配属性值为字符串开头的方法
driver.find_element(By.CSS_SELECTOR,"#qcreatetask[class^='plac']")
#CSS定位,匹配属性值字符串结尾的方法
driver.find_element(By.CSS_SELECTOR,"#qcreatetask[class$='italic']")
#CSS定位,匹配被-分割的属性值的方法
driver.find_element(By.CSS_SELECTOR,"#qcreatetask[class|='placeholder']")
#通过XPATH属性定位
driver.find_element(By.XPATH,"//input[@class='placeholder-italic']")
#XPATH定位,字符串开头starts-with()
driver.find_element(By.XPATH,"//input[starts-with(@class,'pla')]")
#XPATH定位,字符串结尾ends-with()
driver.find_element(By.XPATH,"//input[ends-with(@class,'italic')]")
#XPATH定位,包含某字符串contains()
driver.find_element(By.XPATH,"//input[contains(@class,'holder')]")
driver.quit()