//update session variable with ajax
function reloadCaptcha() {


  if(document.all) {
    var XhrObj = new ActiveXObject("Microsoft.XMLHTTP") ;
  } else {
    var XhrObj = new XMLHttpRequest();
  }
  
  XhrObj.open("POST", "captcha_ajax.asp");
  XhrObj.onreadystatechange = function() {
    if (XhrObj.readyState == 4 && XhrObj.status == 200) {
      changeCaptchaImages();
    }
  }
  XhrObj.setRequestHeader('Content-Type','application/x-www-form-urlencoded');
  XhrObj.send('');
}

//update images
function changeCaptchaImages() {
  var n=1;
  while (document.getElementById('captcha'+n)) {
    document.getElementById('captcha'+n).src='captcha_image.asp?id='+n+'&refdate='+Date();
    n++;
  }
}