ajax 第十节 ajax请求重复发送问题
=================服务端响应==================
//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('/cache', (request, response) => {
//设置响应头，设置充许跨域
response.setHeader('Access-Control-Allow-Origin', '*');
setTimeout(() => {
response.send('name-xxxxx');
}, 3000);
})
// 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.......');
})
=================取消客户端请求重复发送==================
<!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>Document</title>
<style>
#result {
width: 200px;
height: 100px;
border: solid 1px red;
}
.abc {
width: 200px;
height: 100px;
border: solid 1px pink;
}
</style>
</head>
<body>
<button>发送请求</button>
</body>
<script>
const btn = document.querySelector('button');
let xhr = null;
let issending = false;
btn.onclick = function () {
if (issending) xhr.abort();
xhr = new XMLHttpRequest();
issending = true;
xhr.open('GET', 'http://127.0.0.1:8000/cache');
xhr.send();
xhr.onreadystatechange = function () {
if (xhr.readystate == 4) {
issending = false;
}
}
}
</script>
</html>
