AJAX的几种请求方法
1.GET
<!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>
<style>
#result {
width: 200px;
height: 100px;
border: solid 1px #90b;
}
</style>
<body>
<button>点击发送请求</button>
<div id="result">
</div>
</body>
</html>
<script>
//获取button元素
const btn = document.getElementsByTagName('button')[0];
//绑定事件
btn.onclick = function() {
//1.创建对象
const xhr = new XMLHttpRequest();
const result = document.getElementById("result")
//2.设置初始化
xhr.open('GET', 'http://127.0.0.1:8000/server?a=100&b=200');
//3.发送
xhr.send();
//4.事件绑定 处理服务器返回的结果
xhr.onreadystatechange = function() {
if (xhr.readyState === 4) {
if (xhr.status >= 200 && xhr.status < 300) {
//处理结果 行 头 空行 体
//1.响应行
// console.log(xhr.status);//状态码
// console.log(xhr.statusText);//状态字符串
// console.log(xhr.getAllResponseHeaders());//所有响应头
// console.log(xhr.response);//响应体
result.innerHTML = xhr.response;
} else {}
}
}
}
</script>
2.POST
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>AJAX POST 请求</title>
</head>
<style>
#result {
width: 200px;
height: 100px;
border: solid 1px #90b;
}
</style>
<body>
<div id="result">
</div>
<script>
//获取元素对象
const result = document.getElementById("result");
//绑定事件
result.addEventListener("mouseover", function() {
// console.log("test");
//1.创建对象
const xhr = new XMLHttpRequest();
const result = document.getElementById('result')
//2.初始化
xhr.open('POST', 'http://127.0.0.1:8000/server');
//设置请求头
xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
xhr.setRequestHeader('name', 'atguigu')
//3.发送
xhr.send('a:100&b:200&c:300');
//4.事件绑定
xhr.onreadystatechange = function() {
//判断
if (xhr.readyState === 4) {
if (xhr.status >= 200 && xhr.status < 300) {
//处理结果服务端返回的结果
result.innerHTML = xhr.response;
} else {}
}
}
})
</script>
</body>
</html>
3.JSON
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>AJAX POST 请求</title>
</head>
<style>
#result {
width: 200px;
height: 100px;
border: solid 1px #90b;
}
</style>
<body>
<div id="result">
</div>
<script>
const result = document.getElementById('result');
//绑定键盘按下事件
window.onkeydown = function() {
//发送请求
const xhr = new XMLHttpRequest();
//设置响应体数据的类型
xhr.responseType = "json";
//初始化(原来的/server改成/json-server了)
xhr.open('GET', 'http://127.0.0.1:8000/json-server');
//发送
xhr.send();
//事件绑定
xhr.onreadystatechange = function() {
if (xhr.readyState === 4) {
if (xhr.status >= 200 && xhr.status < 300) {
// console.log(xhr.response);
// result.innerHTML = xhr.response;
//手动对数据转换
// let data = JSON.parse(xhr.response);
console.log(data);
// result.innerHTML = data.name;
//自动转换(xhr.responseType = "json";)
console.log(xhr.response)
result.innerHTML = xhr.response.name;
} else {
}
}
}
}
</script>
</body>
</html>
总的后台文件
//引入express
const express =require('express');
global.fetch = require("node-fetch");
//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.get('/server',(request,response)=>{
//设置响应 允许跨域
response.setHeader('Access-Control-Allow-Origin','*');
//设置响应体
response.send('HELLO AJAX');
});
//可以接受任意类型的请求
app.all('/server',(request,response)=>{
//设置响应头 允许跨域
response.setHeader('Access-Control-Allow-Origin','*');
//响应头
response.setHeader('Access-Control-Allow-Headers','*')
//设置响应体
response.send('HELLO AJAX POST-2');
});
//JSON响应
app.all('/json-server',(request,response)=>{
//设置响应头 允许跨域
response.setHeader('Access-Control-Allow-Origin','*');
//响应头
response.setHeader('Access-Control-Allow-Headers','*')
//响应一个数据
const data ={
name:'atguigu'
}
//对对象进行字符串转换
let str = JSON.stringify(data);
//设置响应体
response.send(str);
});
app.all('/server',(request,response)=>{
//设置响应头 允许跨域
response.setHeader('Access-Control-Allow-Origin','*');
//响应头
response.setHeader('Access-Control-Allow-Headers','*')
//设置响应体
response.send('HELLO AJAX POST-2');
});
//针对IE缓存
app.all('/ie',(request,response)=>{
//设置响应头 允许跨域
response.setHeader('Access-Control-Allow-Origin','*');
//响应头
response.setHeader('Access-Control-Allow-Headers','*')
//设置响应体
response.send('HELLO IE');
});
//延时处理
app.all('/delay',(request,response)=>{
//设置响应头 允许跨域
response.setHeader('Access-Control-Allow-Origin','*');
setTimeout(()=>{
//设置响应体
response.send('延时响应')
})
//响应头
response.setHeader('Access-Control-Allow-Headers','*')
//设置响应体
response.send('HELLO IE');
});
//axios服务
app.all('/axios-server',(request,response)=>{
//设置响应头 允许跨域
response.setHeader('Access-Control-Allow-Origin','*');
response.setHeader('Access-Control-Allow-Headers','*')
//设置响应体
const data = {name:'尚硅谷'}
response.send(JSON.stringify(data));
});
//fetch服务
app.all('/fetch-server',(request,response)=>{
//设置响应头 允许跨域
response.setHeader('Access-Control-Allow-Origin','*');
response.setHeader('Access-Control-Allow-Headers','*')
//设置响应体
const data = {name:'尚硅谷'}
response.send(JSON.stringify(data));
});
//监听端口
app.listen(8000,()=>{
console.log("服务已经启动,8000端口监听中...")
});
ps:运用了express和自动重启工具nodemon