python+selenium之——错误：selenium.common.exceptions.WebDriverException: Message: ‘geckodriver’ executable needs to be in PATH.
此时，需要自己配置geckodriver
- 下载geckodriver，地址：https://github.com/mozilla/geckodriver/releases
- 下载后解压得到geckodriver.exe
- 将geckodriver.exe放到Firefox的安装目录下
- 将火狐安装目录添加到环境变量path中
- 重启IDLE
