// stores the reference to the XMLHttpRequest object
var xmlHttp = createXmlHttpRequestObject(); 

// retrieves the XMLHttpRequest object
function createXmlHttpRequestObject() 
{	
  // will store the reference to the XMLHttpRequest object
  var xmlHttp;
  // if running Internet Explorer <= 6.0
  if(window.ActiveXObject) {
    try {
      xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
    }
    catch (e) {
      xmlHttp = false;
    }
  }
  // if running Mozilla or other browsers
  else {
    try {
      xmlHttp = new XMLHttpRequest();
    }
    catch (e) {
      xmlHttp = false;
    }
  }
  // return the created object or display an error message
  if (!xmlHttp)
    alert("Error creating the XMLHttpRequest object.");
  else 
    return xmlHttp;
}

// make asynchronous HTTP request using the XMLHttpRequest object 
function openUrl(UrlToRequest) {
  returnOutput('<div style=\'width:100%;text-align:center;\'><img src=\'/images/ajaxload.gif\' width=\'16\' height=\'16\' alt=\'\' /></div>');
  // proceed only if the xmlHttp object isn't busy
  if (xmlHttp.readyState == 4 || xmlHttp.readyState == 0)
  {
    // execute the ratesxml.php page from the server
    // var UrlToRequest = "http://www.viagaribaldi12.it/listenozze/online/liste.php";
    xmlHttp.open("GET", UrlToRequest, true);  
    // define the method to handle server responses
    xmlHttp.onreadystatechange = handleServerResponse;
    // make the server request
    xmlHttp.send(null);
  }
  else
    // if the connection is busy, try again after one second  
    setTimeout('openUrl('+UrlToRequest+')', 1000);
}

// restituisce output
function returnOutput(stringa) {
    document.getElementById('AreaDinamica').innerHTML = stringa;
}

// executed automatically when a message is received from the server
function handleServerResponse() {
  // move forward only if the transaction has completed
  if (xmlHttp.readyState == 4) {
    // status of 200 indicates the transaction completed successfully
    if (xmlHttp.status == 200) {
        // read the message from the server
        var txtResponse = xmlHttp.responseText;
        // obtain the text's document element
        returnOutput(txtResponse);
    }
  }
}