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.");
 }
}
var receiveReq = getXmlHttpRequestObject();
function makeRequest(url, param) {
	//alert("hi");
//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);
 }   
}

function updatePage() {
 //Check if our response is ready
 if (receiveReq.readyState == 4) {
	 
   //Set the content of the DIV element with the response text
    //alert(receiveReq.responseText);
   document.getElementById('result').innerHTML = receiveReq.responseText;
  
   if(receiveReq.responseText=="Validation string not valid! ")
   {
	document.getElementById("proceed").disabled=true;   
   }
   else  if(receiveReq.responseText=="")
   {
	document.getElementById("proceed").disabled=false;      
   }
   
   //Get a reference to CAPTCHA image
   //img = document.getElementById('imgCaptcha'); 
   //Change the image
   //img.src = 'create_image.php?' + Math.random();
 }
}

function getParam(theForm) {
 //Set the URL
 var url = 'captcha.php';

 //Set up the parameters of our AJAX call
 var postStr = theForm.validation_code.name + "=" + encodeURIComponent( theForm.validation_code.value );
 //alert(postStr);
 //Call the function that initiate the AJAX request
 makeRequest(url, postStr);
}