Hello I need help using AJAX to pull information from my Xml and post into html

I have a assignment that ask for certain information to be pulled from the xml using ajax. So far I have my html, information.xml and below is my code : I also have in the body. My question is how would I pull information from my xml to load onto the html.

    function loadinfo() {
        xmlhttp = new XMLHttpRequest();
        xmlhttp.onreadystatechange= readinfo()
            xmlhttp.open("GET", "information.xml", true);
            xmlhttp.send();
        }


    function readinfo() {
        if (xmlhttp.readyState == 4) {
            xmlDoc = xmlhttp.informationXML;

            var items = xmlDoc.getElementsByTagName("TechnicalSupport")
            root = xmlResponse.documentElement;
            grabinfo = root.getElementsByTagName("TechnicalSupport")



        }
    }

This is my Xml

TechnicalSupport

info online-phone="1-800-588-7885" online-email="TechnicalSupport@html.edu" campus-phone="1-800-588-7886" campus-email="CampusSupport@html.edu"/

TechnicalSupport