var http_request = false;
var debug = false; // Set to true to show the full server response
var oldSessionId = '';

ajax('POST', 'include/files/session.asp', '', 'sessionstatus');
setInterval("ajax('POST', 'include/files/session.asp', '', 'sessionstatus')", 60000);

function ajax(httpRequestMethod, url, parameters, target)
{
  http_request = false;
  document.getElementById(target).value = 'Wait...'
  if (window.XMLHttpRequest)
  { // For Mozilla, Safari, Opera, IE7
    http_request = new XMLHttpRequest();
    if (http_request.overrideMimeType)
    {
      http_request.overrideMimeType('text/plain');
      //Change MimeType to match the data type of the server response.
      //Examples: "text/xml", "text/html", "text/plain"
    }
  }
  else if (window.ActiveXObject)
  { // For IE6
    try
    {
      http_request = new ActiveXObject("Msxml2.XMLHTTP");
    }
    catch (e)
    {
      try
      {
        http_request = new ActiveXObject("Microsoft.XMLHTTP");
      }
      catch (e)
      {}
    }
  }
  if (!http_request)
  {
    //Giving up :( Cannot create an XMLHTTP instance
    return false;
  }
  http_request.onreadystatechange = function() {updateElement(target);};
  if (httpRequestMethod == 'GET')
  {
    http_request.open('GET', url + '?' + parameters, true);
    http_request.send(null);
    ser = ser + 1;
  }
  else if (httpRequestMethod == 'POST')
  {
    http_request.open('POST', url, true);
    http_request.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
    http_request.send(parameters);
  }
}

function updateElement(target)
{
  if (http_request.readyState == 4)
  {
    if (debug == true)
    {
      //alert(http_request.responseText);
    }
    if (http_request.status == 200)
    {
      if (oldSessionId == '')
      {
        oldSessionId = http_request.responseText;
      }
      if (http_request.responseText == oldSessionId)
      {
        document.getElementById(target).value = 'Alive';
      }
      else
      {
        document.getElementById(target).value = 'Expired';
      }
    }
  }
}