How to use JavaScript and WebSocket to implement a real-time online questionnaire survey system

How to use JavaScript and WebSocket to implement a real-time online questionnaire survey system

Introduction:
With the continuous development of the Internet, more and more questionnaires have begun to migrate Go online. In order to obtain user feedback in real time, a real-time online questionnaire system becomes a needed tool. This article will introduce how to use JavaScript and WebSocket to implement a simple real-time online questionnaire system, and give specific code examples.

1. Technology selection
When implementing the real-time online questionnaire survey system, we chose to use JavaScript and WebSocket as the key technologies for implementation. JavaScript is a cross-platform, object-oriented scripting language that can be used for browser-side script development. WebSocket is a protocol for full-duplex communication on a single TCP connection, which enables the server to actively push data to the client.

2. System Architecture
The architecture of the real-time online questionnaire survey system is mainly divided into two parts: front-end and back-end.

1. Front-end part
The front-end part mainly includes user interface and JavaScript code. The user interface is responsible for displaying the questionnaire and receiving user feedback, while the JavaScript code is responsible for establishing a WebSocket connection with the backend and receiving the questionnaire results in real time.

2. Backend part
The backend part is mainly responsible for receiving questionnaire answers submitted by users and broadcasting the questionnaire results to all connected clients. The backend can use any server that supports WebSocket, such as Node.js, Java, Python, etc.

3. Implementation steps
1. Front-end implementation
First, we need to introduce the WebSocket-related JavaScript library into the HTML page, as shown below:

<script>
  var socket = new WebSocket("ws://localhost:8080"); // 连接WebSocket服务器

  socket.onopen = function() {
    // 连接建立成功
  };

  socket.onmessage = function(event) {
    // 接收到服务器发送的数据
    var data = JSON.parse(event.data);
    // 处理问卷调查结果
  };

  socket.onclose = function(event) {
    // 连接关闭
  };
</script>

In the above code , we create a WebSocket instance and establish a connection by specifying the server's address and port. We then handle interactions with the server by listening for events such as onopen, onmessage, and onclose.

2. Backend implementation
Next, we need to implement the WebSocket server on the backend to receive the questionnaire answers submitted by the user and broadcast them to all connected clients. Taking Node.js as an example, we can use the ws library to quickly build a WebSocket server.

First, we need to install the ws library:

$ npm install ws

Then, write the server code in Node.js as follows:

const WebSocket = require('ws');
const wss = new WebSocket.Server({ port: 8080 });

wss.on('connection', function(ws) {
  ws.on('message', function(message) {
    // 接收到客户端发送的数据
    // 处理问卷答案
    // 广播问卷调查结果给所有连接的客户端
    wss.clients.forEach(function(client) {
      if (client.readyState === WebSocket.OPEN) {
        client.send(JSON.stringify(result));
      }
    });
  });
});

In In the above code, we first create a WebSocket.Server instance and listen to the specified port. Then, we handle the client's connection request by listening to the connection event. After the connection is successfully established, we listen to the message event to process the message sent by the client. After receiving the message, we processed the questionnaire answers and broadcast the questionnaire results by looping through all connected clients.

4. Summary
Through JavaScript and WebSocket, we can easily implement a real-time online questionnaire survey system. The front end is responsible for displaying the questionnaire and receiving feedback from users, while the back end processes the questionnaire answers submitted by users and broadcasts the questionnaire results to all connected clients in real time. Through WebSocket's full-duplex communication, we can obtain user feedback in real time to better analyze and optimize products.

The above is a simple implementation example of a real-time online questionnaire system. I hope it will be helpful to you in implementing a similar system. Of course, in practical applications, safety, stability, and the improvement of other functions also need to be considered. I wish your online questionnaire system can achieve good results!

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