function probleem

function CheckDublicateNickname() 
{
	var http = createREQ();
	var divReturn = $('return');
	http.onreadystatechange = function() {
		if(http.readyState == 4) {
			if (http.responseText == $('nickname2').value) {
				divReturn.innerHTML = "<p class='reg_error'>Nickname bezet!</p>";
				document.nicknameSrc.src = "img/ico.cross.png";
				$('nickname2').focus();
				return false;
			} else if (http.responseText == "No Result") {
				divReturn.innerHTML = "";
				document.nicknameSrc.src = "img/ico.accept.png";
				return true;
			} else if ($('nickname2').value == '') {
				divReturn.innerHTML = "<p class='reg_error'>Vul een nickname in!</p>";
				document.nicknameSrc.src = "img/ico.cross.png";
				$('nickname2').focus();
				return false;
			}
		}
	}
	http.open("POST", "php/modules/CheckDublicateNickname.php");
	http.setRequestHeader('Content-Type','application/x-www-form-urlencoded');
	http.send("nickname=" + $('nickname2').value)
}

function CheckDublicateNickname() 
{
	var http = createREQ();
	var divReturn = $('return');
	http.onreadystatechange = function() {
		if(http.readyState == 4) {
			if (http.responseText == $('nickname2').value) {
				divReturn.innerHTML = "<p class='reg_error'>Nickname bezet!</p>";
				document.nicknameSrc.src = "img/ico.cross.png";
				$('nickname2').focus();
				return false;
			} else if (http.responseText == "No Result") {
				divReturn.innerHTML = "";
				document.nicknameSrc.src = "img/ico.accept.png";
				return true;
			} else if ($('nickname2').value == '') {
				divReturn.innerHTML = "<p class='reg_error'>Vul een nickname in!</p>";
				document.nicknameSrc.src = "img/ico.cross.png";
				$('nickname2').focus();
				return false;
			}
		}
	}
	http.open("POST", "php/modules/CheckDublicateNickname.php");
	http.setRequestHeader('Content-Type','application/x-www-form-urlencoded');
	http.send("nickname=" + $('nickname2').value)
}

function CheckRegistrationForm()
{
	var msg = "Volgende velden zijn niet of onjuist ingevuld: \n\n";
	var error = false;
	var nickname = $('nickname2').value;
	var email = $('email').value;
	var captcha = $('security_code').value;
	
	if (nickname == "") { 
		msg += "- Nickname \n"; 
		var error = true; 
	} 
	if (email == "") { 
		msg += "- E-mailadres \n"; 
		var error = true; 
	}
	if (captcha == "") {
		msg +="- Controle \n";
		var error = true;
	}
	if (error) { 
		alert(msg); return false;
	}
	if (CheckDublicateNickname() == true) {
		alert("test");
	}
}

function CheckRegistrationForm()
{
	var msg = "Volgende velden zijn niet of onjuist ingevuld: \n\n";
	var error = false;
	var nickname = $('nickname2').value;
	var email = $('email').value;
	var captcha = $('security_code').value;
 
	if (nickname == "") { 
		msg += "- Nickname \n"; 
		var error = true; 
	} 
	if (email == "") { 
		msg += "- E-mailadres \n"; 
		var error = true; 
	}
	if (captcha == "") {
		msg +="- Controle \n";
		var error = true;
	}
	if (error) { 
		alert(msg); return false;
	}
	if (CheckDublicateNickname() == true) {
		alert("test");
	}
}