XMLHttpRequest Sınıfı

constructor
Şöyle yaparız.

if (window.XMLHttpRequest) {
  // code for IE7+, Firefox, Chrome, Opera, Safari
  xmlhttp = new XMLHttpRequest();
} else {
  // code for IE6, IE5
   xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
}

open metodu
Örnek
Şöyle yaparız

var xhr = new XMLHttpRequest();

xhr.withCredentials = true;

xhr.open("POST", "https://apiurl");

xhr.send(data);
  xhr.addEventListener("readystatechange", function() {
  console.log("readyState="+this.readyState);

    if(this.readyState === 4) {

      console.log("status="+this.status);
      console.log("response="+this.responseText);
      document.getElementById("demo").innerHTML = this.status+" "+this.responseText;

     }
  }); 
  return false;
}

Örnek
Örnek ver.