function checkLogin() {
	var formLogin = document.getElementById("formLogin");		
	var msgLogin = document.getElementById("msgLogin");	
	
	
		var oXmlHttp = zXmlHttp.createRequest();
		oXmlHttp.open("get", "ajaxphp/registerForm.php?formLogin" + "=" + encodeURIComponent(formLogin.value), true);
		oXmlHttp.onreadystatechange = function () {

			if (oXmlHttp.readyState == 4) {
			
				if (oXmlHttp.status == 200) {		
					msgLogin.style.color = "#FF0000";
				
					var data = JSON.parse(oXmlHttp.responseText);
					if (formLogin.value == "") {
						data.msg = "Wprowadz jakis tekst.";	 
					} 
					show(data, "msgLogin");
				} else {
//					showError();
				};
			}
		}
    oXmlHttp.send(null);		
 
};

function show(data, where) {
	var what = document.getElementById(where);		
	if (data.error == 1) {
			what.innerHTML = data.msg;
			
	} else {
		what.innerHTML = "Wybrana nazwa jest wolna.";
		what.style.color = "#009900";
	}
}