JSFiddle - React, Tailwind, and code Playground

JavaScript

var formData = new FormData();
formData.append("html", null);
var xhr = new XMLHttpRequest();
xhr.open("POST", "/echo/html/");
xhr.onreadystatechange = function() {
    if (xhr.readyState == 4) alert(xhr.responseText);
};
xhr.send(formData);