JSON.stringfy chinese garbled in node?

  node.js, question

After submitting the form, the browser will look at the Chinese character string and try to find a solution.

The index.htm file code is as follows:

<html>
 <body>
 <form action="http://127.0.0.1:8081/process_get" method="GET">
 First Name: <input type="text" name="first_name">  <br>
 
 Last Name: <input type="text" name="last_name">
 <input type="submit" value="Submit">
 </form>
 </body>
 </html>

Js file code is as follows:

var express = require('express');
 var app = express();
 
 app.use(express.static('public'));
 
 app.get('/index.htm', function (req, res) {
 Res.sendFile( __dirname plus "/"plus "index.htm");
 })
 
 app.get('/process_get', function (req, res) {
 
 //output JSON format
 response = {
 first_name:req.query.first_name,
 last_name:req.query.last_name
 };
 console.log(response);
 res.end(JSON.stringify(response));
 })
 
 var server = app.listen(8081, function () {
 
 var host = server.address().address
 var port = server.address().port
 
 Log ("application instance, access address is http:// percent s: percent s", host, port)
 
 })

Is the encoding of the browser utf-8?