Salve...

Ho fatto un esempio preso da un libro.... quando carico il file hml...ho il seguente errore:
"errore durante la lettura della risposta: Type error 'xmlresponse' non è definito. "

file html
codice:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11.dtd">
<html>
<head>
<title>AJAX in pratica: Usare php dom </title>
<script type="text/javascript" src= "phptest.js"></script>
</head>
<body onload= "process()">
Il libro su AJAX del 2006 è:


<div id="myDivElement"/>
</body>
</html>
file phptest.js
codice:
 
var xmlHttp = createXmlHttpRequestObject();
function createXmlHttpRequestObject()
{
var xmlHttp;
try
{
xmlHttp = new XMLHttpRequest();
}
catch (e)
{
var XmlHttpVersions = new array ("MSXML2.XMLHTTP.6.0",
				"MSXML2.XMLHTTP.5.0",
				"MSXML2.XMLHTTP.4.0",
				"MSXML2.XMLHTTP.3.0",
				"MSXML2.XMLHTTP",
				"Microsoft.XMLHTTP");
for (var i=0; i<XmlHttpVersions.length && !xmlHttp;i++)
{
try
 {
  xmlHttp = new ActiveXObject(XmlHttpVersions[i]);
 }
  catch(e){}
 }
}
if (!xmlHttp)
alert("Errore durante la creazione dell'oggetto XMLHttpRequest.");
else
return xmlHttp;
}
function process()
{
  if (xmlHttp)
  {
    try
    {
    xmlHttp.open("GET", "phptest.php",true);
    xmlHttp.onreadystatechange =handleRequestStateChange;
    xmlHttp.send(null);
    }
   catch (e)
   {
    alert("impossibile collegarsi al server:\n" + e.toString());
   }
  }
}
function handleRequestStateChange()
{
if(xmlHttp.readyState == 4)
   {
   if (xmlHttp.status == 200)
     {
     try
      {
       handleServerResponse();
      }
       catch(e)
        {
          alert("errore durante la lettura della risposta:" + e.toString());
        } 
     }
     else
     {
      alert("C e stato un problema nella ricezione dei dati:\n"+xmlHttp.statusText);
     }
   }
}
function handleServerResponse()
{
   var xmlResponse = xmlHttp.responseXML;
 if (!xmlResponse || !xmlresponse.documentElement)
   throw("Struttura XML non valida:\n" + xmlHttp.responseText);
   var rootNodeName = xmlResponse.documentElement.nodeName;
  if(rootNodeName=="parsererror") throw("Struttura XML non valida");
   xmlRoot =xmlResponse.documentElement;
   titleArray = xmlRoot.getElementsByTagName("title");
   isbnArray = xmlRoot.getElementsByTagName("isbn");
   var html ="";
   for (var i=0; i<titleArray.length;i++)
      html += titleArray.item(i).firstChild.data + ", "+ isbnArray.item(i).firstChild.data + "
";
      myDiv = document.getElementById("myDivElement");
      myDiv.innerHTML= html;
}
file php
codice:
<?php
header("Content-type: text/xml");
$dom= new DOMDocument();
$response =$dom->createElement('response');
$dom->appendChild($response);
$books = $dom->createElement('books');
$response->appendChild($books);
$title = $dom->createElement('title');
$titleText =$dom->createTextNode('Building Responsive Web Application with AJAX and PHP');
$title->appendChild($titleText);
$isbn=$dom->createElement('isbn');
$isbnText = $dom->createTextNode('1-904811-82-5');
$isbn->appendChild($isbnText);
$book= $dom->createElement('book');
$book->appendChild($title);
$book->appendChild($isbn);
$books->appendChild($book);
$xmlString=$dom->saveXML();
echo $xmlString;
?>