var ajaxformobj;
function getXmlHttpRequestObject() {
	if (window.XMLHttpRequest) {
		return new XMLHttpRequest(); //Mozilla, Safari ...
	} else if (window.ActiveXObject) {
		return new ActiveXObject("Microsoft.XMLHTTP"); //IE
	} else {
		alert("Your browser doesn't support the XmlHttpRequest object.");
	}
}
var receiveReq = getXmlHttpRequestObject();
function makeRequest(url, param) {
	if (receiveReq.readyState == 4 || receiveReq.readyState == 0) {
		receiveReq.open("POST", url, true);
		receiveReq.onreadystatechange = updatePage;
		receiveReq.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
		receiveReq.setRequestHeader("Content-length", param.length);
		receiveReq.setRequestHeader("Connection", "close");
		receiveReq.send(param);
	}   
}
function updatePage() {
	if(receiveReq.readyState!=4) {
		document.getElementById("div_checking").innerHTML="<strong>Checking...</strong>";
	}
	if (receiveReq.readyState == 4) {
		document.getElementById("div_checking").innerHTML="";
		var result = receiveReq.responseText;
		if(result!="1") {
			img = document.getElementById('imgCaptcha'); 
			img.src = 'create_image.php?'+Math.random();
			alert("Please enter the Correct Verification Code shown in the image.");
			ajaxformobj.txt_capcha.focus();
			return false;
		} else {
			ajaxformobj.submit();
		} 
	}
}
function getParam(theForm) {
	ajaxformobj = theForm;
	var url = 'captcha.php';
	var postStr = theForm.txt_capcha.name+"="+encodeURIComponent(theForm.txt_capcha.value);
	makeRequest(url, postStr);
}