function createObject() {
var tipo_richiesta;
var browser = navigator.appName;
if(browser == "Microsoft Internet Explorer"){
tipo_richiesta = new ActiveXObject("Microsoft.XMLHTTP");
}else{
tipo_richiesta = new XMLHttpRequest();
}
return tipo_richiesta;
}

var http = createObject();

function token() {
http.open('get', 'token.php');
http.onreadystatechange = handleResponseToken;
http.send(null);
}

function handleResponseToken() {
if(http.readyState == 4){
var response = http.responseText;
document.getElementById('testtoken').value = response;
}
}