제가 잘못 클릭해서 완료를 눌렀네요 ,,,

index 코드

    <script>

        $(document).ready(function () {

            show_order();

        });

        function show_order() {

            fetch('/mars').then((res) => res.json()).then((data) => {

                console.log(data)

                alert(data['msg'])

            })

        }

        function save_order() {

            let name= $('#name').val();

            let address= $('#address').val();

            let size= $('#size').val();

            let formData = new FormData();

            formData.append("name_give", name);

            formData.append("address_give", address);

            formData.append("size_give", size);

            fetch('/mars', { method: "POST", body: formData }).then((res) => res.json()).then((data) => {

                alert(data["msg"]);

            });

        }

    </script>

app 코드

from flask import Flask, render_template, request, jsonify

app = Flask(__name__)

from pymongo import MongoClient

client = MongoClient('mongodb+srv://wonnoel93:wonch02422@noelwon.2dxqprz.mongodb.net/?retryWrites=true&w=majority')

db = client.dbwonnoel93

@app.route('/')

def home():

    return render_template('index.html')

@app.route("/mars", methods=["POST"])

def mars_post():

    name_receive = request.form['name_give']

    address_receive = request.form['address_give']

    size_receive = request.form['size_give']

    doc = {

        'name':name_receive,

        'address':address_receive,

        'size':size_receive

    }

    db.mars.insert_one(doc)

    return jsonify({'msg':'DATA 저장완료!'})

@app.route("/mars", methods=["GET"])

def mars_get():

    return jsonify({'msg':'GET 연결 완료!'})

if __name__ == '__main__':

    app.run('0.0.0.0', port=5000, debug=True)

이렇게 작성되어 있습니다.