var qstring = null;
function get_ajax(query, mod, frm, url){
	var ajaxRequest;
	
	try{
		ajaxRequest = new XMLHttpRequest();
	} catch (e){
		try{
			ajaxRequest = new ActiveXObject("Msxml2.XMLHTTP");
		} catch (e) {
			try{
				ajaxRequest = new ActiveXObject("Microsoft.XMLHTTP");
			} catch (e){
				alert("Ajax hívás nem támogatott!");
			}
		}
	}
	
	ajaxRequest.onreadystatechange = function(){
		if(ajaxRequest.readyState == 4){
			if(ajaxRequest.responseText.indexOf('#e0') !=  -1 ||
				ajaxRequest.responseText.indexOf('error') != -1 ||
				ajaxRequest.responseText.indexOf('Notice') != -1 ||
				ajaxRequest.responseText.indexOf('Fatal error') != -1 ||
				ajaxRequest.responseText.indexOf('Parse error') != -1)
					return alert('Hiba üzenet!\n'+ajaxRequest.responseText);
					
			
			if(mod == 0){ //városok
				if(frm.varosok) frm.varosok.disabled = false;
				$('varosok').innerHTML = ajaxRequest.responseText;
			}
			if(mod == 2){ //user
				if(frm.fnev) frm.fnev.disabled = false;
				if(ajaxRequest.responseText == 1){
					  frm.fnev.value = '';
					  $('fnev_check').innerHTML = '<div style="color:red">A felhasználói név már foglalt!</div>';	
				}else $('fnev_check').innerHTML = '';
			}
			if(mod == 3){ //mail
				if(frm.mail) frm.mail.disabled = false;
				if(ajaxRequest.responseText == 1){
						frm.mail.value = '';
						$('mail_check').innerHTML = '<div style="color:red">Az e-mail cím már szerepel adatbázisunkban!</div>';	
				}else	$('mail_check').innerHTML = '';	
			}
			
		}else{
			if(mod == 0){ //városok
				if(frm.varosok) frm.varosok.disabled = true;
			}
			if(mod == 2){ //városok
				if(frm.fnev) frm.fnev.disabled = true;
			}
			if(mod == 3){ //városok
				if(frm.mail) frm.mail.disabled = true;
			}
		}
	}
	
	qstring = query;
	ajaxRequest.open("GET", url+"reg_datas.php?"+query, true);
	//alert("datas.php?"+query);
	ajaxRequest.send(null); 
}