class modal{
 request = new XMLHttpRequest();

 send = (dataType, url, data) => {
  this.request.open(dataType, url, true);
  this.request.send(data);
 }

 innerData = ()=>{

 }

 onreadystatechange = () => {
  if (this.request.readyState < 4) {
   console.log(this.request);
   console.log(this.request.responseText);
   console.log("Данные еще не пришли");
  }
  if(this.request.readyState == 4){
   console.log(this.request);
   console.log(this.request.responseText);
   console.log("Данные пришли");
  }
 };

 constructor(){
  this.request.onreadystatechange = this.onreadystatechange();
  this.send("POST", "/modal/zapros_cena.php", 1);
  return this.request.responseText;
 }
}

onreadystatechange = () => {
  if (this.request.readyState < 4) {
   console.log(this.request);