axios.post('', {
    data: params
},{
    headers: {
        'Access-Control-Allow-Origin':'*',  //解决cors头问题
        'Access-Control-Allow-Credentials':'true', //解决session问题
        'Content-Type': 'application/x-www-form-urlencoded; charset=UTF-8' //将表单数据传递转化为form-data类型
    },
    withCredentials : true
})
    .then(function (response) {
        var res = response.data;
        if(res=="登录成功,3秒后跳转主页") {
            var noticeId= JSON.parse(window.sessionStorage.getItem('user'));
            alert(noticeId)
            alert(response.data);
            setTimeout(that.LoginSuccess, 3000)
        }else if(response.data=="用户名不存在,请注册后重新登录") {
            that.message = response.data
        }
    })
    .catch(function (error) {
        alert(error);
    });

Flask

from flask import Flask, request,make_response,jsonify
import json
from flask_cors import CORS
app = Flask(__name__)
CORS(app, supports_credentials=True)