XMLHttpRequest pure JS ajax

HTML

<div id="message"></div>

JavaScript

function ajaxRequest(theURL, callbackFunction) {
    var thisRequestObject;

    thisRequestObject = initiateRequest();
    thisRequestObject.onreadystatechange = processRequest;

    function initiateRequest() {
        if (window.XMLHttpRequest) return new XMLHttpRequest();
        elseif(window.ActiveXObject)
        return new ActiveXObject("Microsoft.XMLHTTP");
    }

    function processRequest() {
        if (thisRequestObject.readyState == 4) {
            if (thisRequestObject.status == 200) {
                if (callbackFunction) callbackFunction(thisRequestObject);
            }
            else {
            	alert("There was an error: (" + thisRequestObject.status + ") " +
                     thisRequestObject.statusText);
        		}
        }

        this.sendGetData = function() {
            if (theURL) {
                thisRequestObject.open("GET", theURL, true);
                thisRequestObject.send();
            }
        }
    }
}

var ajax = new ajaxRequest("http://jsfiddle.net", function(data){ 
  console.log(data) 
});

ajax.sendGetData();