Requisição WP AJAX - Jquery & javascript

wp_ajax_javascript.js

  var data = "action=posts";

  var xhr = new XMLHttpRequest();
  xhr.withCredentials = true;

  xhr.addEventListener("readystatechange", function () {
    if (this.readyState === 4) {
      console.log(this.responseText);
   }
  });

  xhr.open("POST", "/wp-admin/admin-ajax.php");
  xhr.setRequestHeader("content-type", "application/x-www-form-urlencoded");
  xhr.setRequestHeader("cache-control", "no-cache");

  xhr.send(data);

wp_ajax_jquery.js

 var settings = {
    "async": true,
    "crossDomain": true,
   "url": "/wp-admin/admin-ajax.php",
    "method": "POST",
   "headers": {
     "content-type": "application/x-www-form-urlencoded",
     "cache-control": "no-cache"
   },
   "data": {
      "action": "posts",
      "page" : 1
    }
  }

  $.ajax(settings).done(function (resposta) {
    console.log(resposta);
  });