// 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
  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;
}

// sends GET request to link and handles the results with handle function
function sendRequest(link, handle)
{
  // proceed only if the xmlHttp object isn't busy
  if (xmlHttp.readyState == 4 || xmlHttp.readyState == 0)
  {
    // execute the quickstart.php page from the server
    xmlHttp.open("GET", link, true);
    // define the method to handle server responses
    xmlHttp.onreadystatechange = handle;
    // make the server request
    xmlHttp.send(null);
  }
  else
    // if the connection is busy, try again after one second
    setTimeout('sendRequest(\''+link+'\', '+handle+')', 1000);
}

function getXmlResults()
{
  // move forward only if the transaction has completed
  if (xmlHttp.readyState == 4)
  {
    // status of 200 indicates the transaction completed success
    if (xmlHttp.status == 200)
    {
      // extract the XML retrieved from the server
      var xmlResponse = xmlHttp.responseXML;
      // obtain the document element (the root element) of the XML
      var xmlDocumentElement = xmlResponse.documentElement;
      // get the text message, which is in the first child of
      // the the document element
      return xmlDocumentElement;
    }
    // a HTTP status different than 200 signals an error
    else
    {
      alert("There was a problem accessing the server: " + xmlHttp.statusText);
    }
    return false;
  }
}

function getTextResults()
{
  // move forward only if the transaction has completed
  if (xmlHttp.readyState == 4)
  {
    // status of 200 indicates the transaction completed success
    if (xmlHttp.status == 200)
    {
      // extract the XML retrieved from the server
      var xmlResponse = xmlHttp.responseText;
      // obtain the document element (the root element) of the XML
      //var xmlDocumentElement = xmlResponse.documentElement;
      // get the text message, which is in the first child of
      // the the document element
      //return xmlDocumentElement;
      return xmlResponse;
    }
    // a HTTP status different than 200 signals an error
    else
    {
      alert("There was a problem accessing the server: " + xmlHttp.statusText);
    }
    return false;
  }
}