PWA - Ajax

function carregarPrimary(a,b) {

    var xmlhttp = new XMLHttpRequest();

    xmlhttp.onreadystatechange = function() {

        if (this.readyState == 4 && this.status == 200) {

            document.getElementById("idPrimary").innerHTML = this.responseText;

        } else if(this.readyState == 4 && this.status == 0) {

            document.getElementById("idInternet").style.display='block';

        }

    };

    xmlhttp.open("GET", "https://artincode.pt/index.php?nome="+a+"&apelido="+b, true);

    xmlhttp.send();

}