getXHR

gistfile1.js

function getXHR(url, callback) {
    var req = new XMLHttpRequest();
    req.onreadystatechange = function() {
        if (this.readyState == 4) {
            if (this.status == 200 || this.status == 0) {
                callback(this.responseText);

            } else {
                alert('Request failed')
            }
        }
    }
    req.open("GET", url, true);
    req.send();
}