//Gets the browser specific XmlHttpRequest Object 
function getXmlHttpRequestObject() {
 if (window.XMLHttpRequest) {
    return new XMLHttpRequest(); //Mozilla, Safari ...
 } else if (window.ActiveXObject) {
    return new ActiveXObject("Microsoft.XMLHTTP"); //IE
 } else {
    //Display our error message
    alert("Your browser doesn't support the XmlHttpRequest object.");
 }
}

//Our XmlHttpRequest object
var receiveReq = getXmlHttpRequestObject();


//Initiate the AJAX request
function makeRequest(url, param) {
//If our readystate is either not started or finished, initiate a new request
 if (receiveReq.readyState == 4 || receiveReq.readyState == 0) {
   //Set up the connection to captcha_test.html. True sets the request to asyncronous(default) 
   receiveReq.open("POST", url, true);
   //Set the function that will be called when the XmlHttpRequest objects state changes
   receiveReq.onreadystatechange = updatePage; 

   //Add HTTP headers to the request
   receiveReq.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
   receiveReq.setRequestHeader("Content-length", param.length);
   receiveReq.setRequestHeader("Connection", "close");

   //Make the request
   receiveReq.send(param);
 }   
}

//Called every time our XmlHttpRequest objects state changes
function updatePage() {
 //Check if our response is ready
 if (receiveReq.readyState == 4) {
   
   if (receiveReq.responseText != "true") {
     //Set the content of the DIV element with the response text
     document.getElementById('result').innerHTML = receiveReq.responseText;
     //Get a reference to CAPTCHA image
     img = document.getElementById('imgCaptcha'); 
     //Change the image
     img.src = 'captcha-create-image.php?' + Math.random();
   } else {
     document.form.submit();
   }
 }
}

//Called every time when form is perfomed
function getParam(theForm) {
  //Set the URL
  var url = 'captcha-fin.php';
  //Set up the parameters of our AJAX call
  var postStr = theForm.txtCaptcha.name + "=" + encodeURIComponent( theForm.txtCaptcha.value );
  //Call the function that initiate the AJAX request
  makeRequest(url, postStr);
}

// refresh l'image du captcha
function refreshImage() {
  //Set the URL
  var url = 'captcha-create-image.php';
  //Set up the parameters of our AJAX call
  var postStr = "";
  //Call the function that initiate the AJAX request
  makeRequest(url, postStr);
}

function refreshImage2() {
     //Get a reference to CAPTCHA image
   img = document.getElementById('imgCaptcha'); 
   //Change the image
   img.src = 'captcha-create-image.php?' + Math.random();
   // controle si l'image est bien chargee
   //setTimeout(refreshImageBroken, 500);
}
/*
function refreshImageBroken() {
   var x = document.getElementById('imgCaptcha').offsetWidth;
   if (x != '100') {
      refreshImage2();      
   }
}
*/