如下图发生了CORS错误，再看看服务端，是一个简单的flask应用可以看出前端的预请求，options是成功的，但是post请求的时候是失败的，Access to XMLHttpRequest at ‘http://127.0.0.1:5000/user/login’ from origin ‘http://localhost:9527’ has been blocked by CORS poli

先看报错：RuntimeError: Working outside of application context.This typically means that you attempted to use functionality thatneeded to interface with the current application object in some way.To solve

先看报错：RuntimeError: Working outside of application context.This typically means that you attempted to use functionality thatneeded to interface with the current application object in some way.To solve

windows安装python3.9.10，一路默认安装下去，安装完成后，cmd窗口输入python确实可以，但是后面发现要创建虚拟环境的时候，pip install virtualenv virtualenvwrapper-win， 提示Defaulting to user installation because normal site-packages is not writeable，意思