从发帖请求收到消息后显示更改

Question

我当前的问题是我想在我的烧瓶网站上显示一个警报，该警报应该在我向烧瓶服务器发布请求后显示。

我已经尝试在JavaScript中进行一些提取。但是我不知道如何使它工作。

fetch('_get_message')
.then(response => response.json())
.then(data => {
    alert(data);
    console.log(data); // Prints result from `response.json()` in getRequest
})
.catch(error => console.error(error))

烧瓶服务器：

@app.route("/_get_message", methods=["POST", "GET"])
def get_message():
    if request.method == "POST":
        received_data = request.data.decode()
        # check received json data
        if received_data == None:
            return "No data found in post", 400
        print(received_data)
        to_display = {"message": received_data}
        return jsonify(to_display)
    elif request.method == "GET":
        return jsonify(to_display)
    else:
        return "Method not allowed", 305