The XMLHttpRequest response property returns the response's body content as an ArrayBuffer, a Blob, a Document, a JavaScript Object, or a string, depending on the value of the request's responseType property.

An appropriate object based on the value of responseType. You may attempt to request the data be provided in a specific format by setting the value of responseType after calling open() to initialize the request but before calling send() to send the request to the server.

The value is null if the request is not yet complete or was unsuccessful, with the exception that when reading text data using a responseType of "text" or the empty string (""), the response can contain the response so far while the request is still in the LOADING readyState (3).

This example presents a function, load(), which loads and processes a page from the server. It works by creating an XMLHttpRequest object and creating a listener for readystatechange events such that when readyState changes to DONE (4), the response is obtained and passed into the callback function provided to load().

The content is handled as raw text data (since nothing here is overriding the default responseType).

const url = "somePage.html"; //A local page

function load(url, callback) {
  const xhr = new XMLHttpRequest();

  xhr.onreadystatechange = () => {
    if (xhr.readyState === 4) {
      callback(xhr.response);
    }
  };

  xhr.open("GET", url, true);
  xhr.send("");
}

• Using XMLHttpRequest
• Getting text and HTML/XML data: XMLHttpRequest.responseText and XMLHttpRequest.responseXML