ajax 第六节 json数据回调手动转换 与 自动转换
＝＝＝＝＝＝＝＝＝＝＝＝手动转换＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>AJAX POST 请求</title>
<style>
#result {
width: 200px;
height: 100px;
border: solid 1px red;
}
</style>
</head>
<body>
<div id="result"></div>
</body>
<script>
const result = document.getElementById('result');
window.onkeydown = function () {
const xhr = new XMLHttpRequest();
xhr.open('GET', 'http://127.0.0.1:8000/json-server')
xhr.send()
xhr.onreadystatechange = function () {
if (xhr.readyState == 4) {
if (xhr.status >= 200 && xhr.status < 300) {
let data = JSON.parse(xhr.response);
console.log(data);
result.innerHTML = data.name
}
}
}
}
</script>
</html>
＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝自动转换＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>AJAX POST 请求</title>
<style>
#result {
width: 200px;
height: 100px;
border: solid 1px red;
}
</style>
</head>
<body>
<div id="result"></div>
</body>
<script>
const result = document.getElementById('result');
window.onkeydown = function () {
const xhr = new XMLHttpRequest();
xhr.responseType = 'json'
xhr.open('GET', 'http://127.0.0.1:8000/json-server');
xhr.send();
xhr.onreadystatechange = function () {
if (xhr.readyState == 4) {
if (xhr.status >= 200 && xhr.status < 300) {
console.log(xhr.response);
result.innerHTML = xhr.response.name
}
}
}
}
</script>
</html>
＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝server.js ＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝
//引用 express
const { request, response, json } = require('express');
const express = require('express');
//创建应用对象
const app = express();
//创建路由规则，
// request 是对请求报文的封装
// response 是对响应报文的封装
//app.all 可以接收任意类型的请求头
app.get('/json-server', (request, response) => {
//设置响应头，设置充许跨域
response.setHeader('Access-Control-Allow-Origin', '*');
const data = {
name: 'username',
}
let str = JSON.stringify(data);
response.send(str);
})
// 监听端口启动服务
app.listen(8000, () => {
console.log('服务已经启动,8000端口监听中.......');
})
