function getXMLHttp2() {
var xmlhttp = null;
if (window.ActiveXObject) {
  if (navigator.userAgent.toLowerCase().indexOf("msie 5") != -1) {
  xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
  } else {
    xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
  }
}
if (!xmlhttp && typeof(XMLHttpRequest) != 'undefined') {
  xmlhttp = new XMLHttpRequest()
}
return xmlhttp
}


function verifica_username(username) {
objHTTP2 = getXMLHttp2();
objHTTP2.open("GET", "http://www.venditoridiauto.it/script/recupera_username.asp?username=" + username, true);
objHTTP2.onreadystatechange= function() {elaboraRisposta2()};
objHTTP2.send(null);
}
function elaboraRisposta2() {
if (objHTTP2.readyState==4) {
document.getElementById("recupera_username").innerHTML = objHTTP2.responseText
}
}