javascript原生ajax请求

     class Ajax{

         constructor(url, method, data, callback_suc, callback_err, callback_run){
             this.RT = true;//默认为异步请求
             this.url = url;
             this.method = method || "POST";
             this.data = data || "";
             this.callback_suc = callback_suc || function () {};
             this.callback_err = callback_err || function () {};
             this.callback_run = callback_run || function () {};
             if(!this.url){this.callback_err(); return;}
             this.createRequest();
         }

         createRequest(){
             let xhr = new XMLHttpRequest();
             xhr.onreadystatechange = (e)=>{this.run(e);}
             xhr.open(this.method, this.url, this.RT);
             xhr.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
             xhr.send(this.data);
         }

         run(e){
             this.callback_run(e);
             if(e.target.readyState !== 4 || e.target.status !== 200){return;}
             this.callback_suc(e);
         }

     }
     //调用:
     new Ajax(
         "./main.php", //url：请求地址
         "POST", //method：请求方法
         "data=3&sb=2",//data：传递数据
         (e)=>{//callback_suc：请求完成 回调函数
             document.write(e.target.responseText);//
         },
         (e)=>{},//callback_err：请求错误 回调函数
         (e)=>{}//callback_run：请求中 回调函数
     )

上面是js代码

下面以main.php为例接收请求

 <?php
     //接收客户端请求数据data和sb
     $data = isset($_POST['data']) ? $_POST['data'] : "data为空";
     $sb = isset($_POST['sb']) ? $_POST['sb'] : "sb为空";
     //向客户端返回数据
     echo $data." ".$sb;
 ?>