/*** 目标：封装_简易axios函数_获取省份列表*  1. 定义myAxios函数，接收配置对象，返回Promise对象*  2. 发起XHR请求，默认请求方法为GET*  3. 调用成功/失败的处理程序*  4. 使用myAxios函数，获取省份列表展示*/function myAxios(config) {return new Promise((resolve, reject) => {const xhr = new XMLHttpRequest()// 查询参数支持if (config.params) {config.url += `?${new URLSearchParams(config.params).toString()}`}xhr.open(config.method || "GET", config.url)xhr.addEventListener("loadend", () => {if (xhr.status >= 200 && xhr.status < 300) {resolve(JSON.parse(xhr.response))} else {reject(new Error(xhr.response))}})// 请求体参数支持if (config.data) {xhr.setRequestHeader("Content-Type", "application/json")xhr.send(JSON.stringify(config.data))} else {xhr.send()}})}myAxios({url: "https://ajax.itheima.net/api/register",method: "post",data: {username: "mayanan04",password: "123456"}}).then(ret => {document.querySelector("p").innerHTML = ret.message}).catch(err => {document.querySelector("p").innerHTML = err.message})