很多小白不知道ajax怎么学，所以就弄了个node后台模拟下基本的ajax请求。
环境要求是安装node~
先上linkMysql.js
var mysql = require('mysql')
var connection = mysql.createConnection({
host: 'localhost',
user: 'root',
password: '', //自己数据库的密码
database: ''//自己数据库的名称
})
function LinkMysql(tableName, key, value) {
connection.connect()
var data = ''
var sql = 'SELECT * FROM ' + tableName +' where ' + key + '=' + value
console.log(sql)
return new Promise(function(resolve,reject) {
connection.query(sql, function(err, result) {
console.log('--------------------------SELECT----------------------------');
console.log(result);
console.log('------------------------------------------------------------
');
resolve(result)
})
})
}
function cutMysql() {
connection.end();
}
module.exports = {
cutMysql,
LinkMysql
}
主JS server.js,提供连接maysql和不连接mysql两种版本
var http = require('http')
var url = require('url');
var util = require('util');
var sqlFunc = require('./linkMysql.js');
// 不连接数据库操作
// var tempJson = [{
// name: '巧克力',
// price: 10
// },{
// name: '薯条',
// price: 20
// }]
http.createServer(function(req, res) {
// 跨域处理
res.setHeader("Access-Control-Allow-Origin", "*");
res.setHeader("Access-Control-Allow-Headers", "X-Requested-With");
res.setHeader("Access-Control-Allow-Methods","PUT,POST,GET,DELETE,OPTIONS");
res.setHeader("X-Powered-By",' 3.2.1');
res.setHeader("Content-Type", "application/json");
var reqUrl = req.url
var mainPath = reqUrl.split('?')[0]
var reqData = reqUrl.split('?')[1].split('=')
if (mainPath == '/test') {
sqlFunc.LinkMysql('goods_info', reqData[0], JSON.stringify(decodeURIComponent(reqData[1]))).then(function(val) {
console.log('从数据库获取数据' + val)
sqlFunc.cutMysql();
res.writeHead(200, {'content-Type': 'text/plain; charset=utf-8'});
res.end(JSON.stringify(val));
})
// 不连接数据库操作
// res.writeHead(200, {'content-Type': 'text/plain; charset=utf-8'});
// res.end(JSON.stringify(tempJson));
} else {
res.writeHead(404, {'content-Type': 'text/plain; charset=utf-8'});
}
}).listen(3000);
console.log('Server running at http://localhost:3000');
最后就是前端html页面了~test.html,用了原生写法，具体的就不讲了百度一大堆~
```<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <meta http-equiv="X-UA-Compatible" content="ie=edge"> <title>Document</title> </head> <body> <div>数据请求</div> <div class="box"></div>
<script>
var xhr = new XMLHttpRequest()
xhr.onreadystatechange = function(){
if (xhr.readyState == 4) {
if ((xhr.status >= 200 && xhr.status < 300) || xhr.status == 304) {
console.log(xhr.responseText)
var data = JSON.parse(xhr.responseText)
var str = ''
for(var i = 0; i < data.length; i ++) {
str += "<div>name: " + data[i].name + "</div><div>price: " + data[i].price + "</div>"
}
document.querySelector('.box').innerHTML = str
} else {
console.log("Request was unsuccessful: " + xhr.status)
}
}
}
xhr.open('get', 'http://localhost:3000/test?name=巧克力', true)
xhr.send(null)
</script>
</body>
</html>
<p>命令行输入<br>node server.js 启动服务 刷新test.html页面就能拿到数据了~</p>
来源：https://segmentfault.com/a/1190000016700988