var xmlHttp = createXmlHttpRequestObject();
var serverAddress = "plib_updatesessionvar.php";
var showErrors = true;
var cache = new Array();
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)
    displayError("Error creating the XMLHttpRequest object.");
  else 
    return xmlHttp;
}
function displayError($message)
{
  if (showErrors)
  {
    showErrors = false;
    alert("Error encountered: \n" + $message);
    setTimeout("validate();", 10000);
  }
}
function UpdateSessionVar(inputVar)
{
  if (xmlHttp)
  {
    inputType=inputVar.type;
    if (inputType=="checkbox")
    {
        if (inputVar.checked)
           inputValue="on";
        else
           inputValue="off";
    }
    else
    {
        inputValue=inputVar.value;
    }
    fieldID=inputVar.id;
    //alert(inputType);
    inputValue = encodeURIComponent(inputValue);
    fieldID = encodeURIComponent(fieldID);
    cache.push("inputValue=" + inputValue + "&fieldID=" + fieldID);
    try
    {
      if ((xmlHttp.readyState == 4 || xmlHttp.readyState == 0) && cache.length > 0)
      {
        var cacheEntry = cache.shift();
        xmlHttp.open("POST", serverAddress, true);
        xmlHttp.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
        xmlHttp.onreadystatechange = handleRequestStateChange;
        xmlHttp.send(cacheEntry);
	 //alert("UpDateSessionVar sent this to the server: inputValue=" + inputValue + "&fieldID=" + fieldID);
      }
    }
    catch (e)
    {
      displayError(e.toString());
    }
  }
}
function handleRequestStateChange() 
{
  if (xmlHttp.readyState == 4) 
  {
    if (xmlHttp.status == 200) 
    {
      try
      {
        //readResponse(); //no response necessary
      }
      catch(e)
      {
        //displayError(e.toString());
      }
    }
    else
    {
      //displayError(xmlHttp.statusText);
    }
  }
}
function readResponse()
{
  var response = xmlHttp.responseText;
  if (response.indexOf("ERRNO") >= 0 || response.indexOf("error:") >= 0 || response.length == 0)
    throw(response.length == 0 ? "Server error." : response);
  responseXml = xmlHttp.responseXML;
  xmlDoc = responseXml.documentElement;
  result = xmlDoc.getElementsByTagName("result")[0].firstChild.data;
  fieldID = xmlDoc.getElementsByTagName("fieldid")[0].firstChild.data;
  message = document.getElementById(fieldID + "Failed");
  message.className = (result == "0") ? "error" : "hidden";
  setTimeout("validate();", 500);
}