// JavaScript Document

function CheckCaptcha(prefix)
{
  var str = document.getElementById(prefix+"_code").value; 
  var value = document.getElementById(prefix+"_value").value;
  //alert("CheckCaptcha:  code="+str+", value="+value);
  if (str == value) {
    document.getElementById(prefix+"_code").value = "";
    return true; }
  document.getElementById(prefix+"_image").src = "captcha/blankcaptcha.jpg";
  //alert("Please enter a correct security code!");
  ajaxCaptchaGetNew(prefix);
  return false; 
}


function ajaxCaptchaGetNew(prefix)
{
  var xmlHttp = ajaxCaptchaGetXmlHttpObject();
  xmlHttp.onreadystatechange = function() { ajaxCaptchaGetNewHandler(xmlHttp,prefix); }
  xmlHttp.open("GET","captcha/getnewcaptcha.php",true);
  xmlHttp.send(null);
}


function ajaxCaptchaGetNewHandler(xmlHttp,prefix)
{
  if(xmlHttp.readyState!=4)
    return;
  var resp = xmlHttp.responseText;
  var iLen = resp.length;
  //alert( "New Captcha resp: "+resp);
  var seccode = resp.substring(iLen, iLen - 5);
  try {
    document.getElementById(prefix+"_code").value = "";
    document.getElementById(prefix+"_image").src = "temp/captcha"+seccode+".jpg";
    document.getElementById(prefix+"_value").value = seccode;
    var x = document.getElementById(prefix+"_value"); }
  catch(e) {
    alert("get xmlHttp response failed"); }
}

function ajaxCaptchaGetXmlHttpObject()
{
var xmlHttp=null;
try {
  // Firefox, Opera 8.0+, Safari
  xmlHttp=new XMLHttpRequest(); }
catch (e)  {
  // Internet Explorer
  try {
    xmlHttp=new ActiveXObject("Msxml2.XMLHTTP"); }
  catch (e) {
    xmlHttp=new ActiveXObject("Microsoft.XMLHTTP"); } }
if (xmlHttp==null) {
  alert ("Your browser does not support AJAX!"); }   
return xmlHttp; 
}