JSFiddle - React, Tailwind, and code Playground

JavaScript

var count = 0;

function doxhr(params) {
    var xhr = new XMLHttpRequest();
    xhr.onreadystatechange = function(evt) {
        if (xhr.readyState === 4) {
            if (xhr.status === 200) {
                params.success(xhr);
            } else {
                throw new Error('eff');
            }
        }
    };
    console.log('opening:',params.url);
    xhr.open("GET", params.url, true);
    xhr.send(null);
};

var params = {
    url: '/',
    success: function() {
        console.log('response',count++,'received');
    }
};

doxhr(params);
doxhr(params);