Flask solves the problem of CORS err

• First of all , You have to make sure your nginx Has been configured to allow cross domain
  for example ：
  stay location Add the following ：

		add_header Access-Control-Allow-Origin *;
		add_header Access-Control-Allow-Methods GET,POST,PUT,DELETE;

• Then install flask Solve cross domain packages
  pip install flask_cors

• How to use it is as follows ：

from flask_cors import CORS
app = Flask(__name__)
CORS(app,supports_credentials=True)