//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-type", "application/octet-stream");
   receiveReq.setRequestHeader("Content-length", param.length);
   receiveReq.setRequestHeader("Connection", "close");

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


//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.");
 }
}


//Called every time our XmlHttpRequest objects state changes
function updatePage()
{
 //Check if our response is ready
 if (receiveReq.readyState == 4)
 {
   //Set the content of the DIV element with the response text
   //document.getElementById('result').innerHTML = receiveReq.responseText;
   //alert(receiveReq.responseText);
   if(receiveReq.responseText>1000)
   {
   		//alert("ok");
   		//alert(document.getElementById('scod').value);
        document.getElementById('scod').value=receiveReq.responseText;
   		//alert(document.getElementById('scod').value);

        document.postform.submit();
        //alert("Ваше сообщение успешно отправлено!");
   }
   else
   {
   		alert("Попробуйте ещё раз ввести число, напечатанное на картинке!");
   //alert(receiveReq.responseText);

   //Get a reference to CAPTCHA image
	   img = document.getElementById('imgCaptcha');
   //Change the image
	   img.src = 'create_image.php?' + Math.random();
   }
 }
}

//Called every time when form is perfomed
function getParam(theForm) {
 //Set the URL
 var url = 'captcha.php';
 //Set up the parameters of our AJAX call
 var postStr = theForm.txtCaptcha.name + "=" + encodeURIComponent( theForm.txtCaptcha.value );
 //postStr+="&iddoc=" + theForm.form_iddoc.value;
 //postStr+="&comment=" + escape( theForm.form_comment.value );
 //postStr+="&author=" + escape( theForm.form_author.value );
 //postStr+="&email=" + escape( theForm.form_email.value );

 //Call the function that initiate the AJAX request
 makeRequest(url, postStr);
}