js监听ajax事件

//监听ajax请求
(function () {
if (typeof window.CustomEvent === "function") return false;

  function CustomEvent(event, params) {
    params = params || {
      bubbles: false,
      cancelable: false,
      detail: undefined,
    };
    var evt = document.createEvent("CustomEvent");
    evt.initCustomEvent(
      event,
      params.bubbles,
      params.cancelable,
      params.detail
    );
    return evt;
  }

  CustomEvent.prototype = window.Event.prototype;

  window.CustomEvent = CustomEvent;
})();
(function () {
  function ajaxEventTrigger(event) {
    var ajaxEvent = new CustomEvent(event, { detail: this });
    window.dispatchEvent(ajaxEvent);
  }

  var oldXHR = window.XMLHttpRequest;

  function newXHR() {
    var realXHR = new oldXHR();

    realXHR.addEventListener(
      "abort",
      function () {
        ajaxEventTrigger.call(this, "ajaxAbort");
      },
      false
    );

    realXHR.addEventListener(
      "error",
      function () {
        ajaxEventTrigger.call(this, "ajaxError");
      },
      false
    );

    realXHR.addEventListener(
      "load",
      function () {
        ajaxEventTrigger.call(this, "ajaxLoad");
      },
      false
    );

    realXHR.addEventListener(
      "loadstart",
      function () {
        ajaxEventTrigger.call(this, "ajaxLoadStart");
      },
      false
    );

    realXHR.addEventListener(
      "progress",
      function () {
        ajaxEventTrigger.call(this, "ajaxProgress");
      },
      false
    );

    realXHR.addEventListener(
      "timeout",
      function () {
        ajaxEventTrigger.call(this, "ajaxTimeout");
      },
      false
    );

    realXHR.addEventListener(
      "loadend",
      function () {
        ajaxEventTrigger.call(this, "ajaxLoadEnd");
      },
      false
    );

    realXHR.addEventListener(
      "readystatechange",
      function () {
        ajaxEventTrigger.call(this, "ajaxReadyStateChange");
      },
      false
    );

    return realXHR;
  }

  window.XMLHttpRequest = newXHR;
})();
window.addEventListener("ajaxReadyStateChange", function (e) {
  e.detail.onload = function () {
    console.log(e, "211111");
  };
});

let xhr = new window.XMLHttpRequest();
xhr.open(
  "GET",
  ""
); //打开一个请求
xhr.send();

怎么拿到请求带过去的参数

获取 请求体 应该 可以 获取吧