前端学习（1417）：ajax实现步骤

ajax.js

// 引用expess框架
const express = require('express');
// 处理路径
const path = require('path');// 创建网站服务器
const app = express();
app.get('/first', (req, res) => {res.send('hello geyao')
})
app.use(express.static(path.join(__dirname)));
// 监听端口
app.listen(3000);
console.log('网站服务器启动成功, 请访问localhost')

ajax.html

<!DOCTYPE html>
<html lang="en"><head><meta charset="UTF-8"><!DOCTYPE html>
<html lang="en"><head><meta charset="UTF-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><title>Document</title>
</head><body><script>//1创建ajax对象var xhr = new XMLHttpRequest();//请求方式xhr.open('get', 'http://localhost:3000/responsdate');//发送请求xhr.send();//获取数据xhr.onload = function() {/* console.log(xhr.responseText); */var res = JSON.parse(xhr.responseText);console.log(res);var str = '<h2></h2>'document.body.innerHTML = str;}</script>
</body></html><meta name="viewport" content="width=device-width, initial-scale=1.0"><title>Document</title>
</head><body><script>//1创建ajax对象var xhr = new XMLHttpRequest();//请求方式xhr.open('get', 'http://localhost:3000/first');//发送请求xhr.send();//获取数据xhr.onload = function() {console.log(xhr.responseText);}</script>
</body></html>

运行结果