function $(key)
{
    if(key.charAt(0)=='#')
    {
        var obj=document.getElementById(key.substr(1));
        if(obj)
        {
            return obj;
        }
        else
        {
            alert('A megadott azonosító nem létezik. : '+key.substr(1));
        }
    }
    else if(key.charAt(0)=='.')
    {
    	var clsName=key.substr(1);

        var retVal = new Array();
        var elements = document.getElementsByTagName("*");
        for(var i = 0;i < elements.length;i++){
            if(elements[i].className.indexOf(" ") >= 0){
                var classes = elements[i].className.split(" ");
                for(var j = 0;j < classes.length;j++){
                    if(classes[j] == clsName)
                        retVal.push(elements[i]);
                }
            }
            else if(elements[i].className == clsName)
                retVal.push(elements[i]);
        }
        return retVal;
    }
    else
    {
        return document.getElementsByTagName(key);
    }
}

window.onload=function()
{
	var elements=$('.js');
	if(elements!=null)
	{
	    for(var i=0; i<elements.length; i++)
	    {
		    elements[i].style.display='block';
	    }
	}
}

function request(url,params,callback)
{
    xmlHttp=null;
    
    try
    {
        xmlHttp=new XMLHttpRequest();
    }
    catch(e)
    {
        ActiveXObjects=[
            'Msxml2.XMLHTTP'
        ];
        for(var i=0; i<ActiveXObjects.length; i++)
        {
            xmlHttp=new ActiveXObject(ActiveXObjects[i]);
            break;
        }
    }
    
    if(xmlHttp===null)
    {
        alert('A böngésző nem támogatja az AJAX-ot.');
    }
    
    xmlHttp.onreadystatechange=function()
    {
        if(xmlHttp.readyState==4)
        {
            if (xmlHttp.status==200)
            {
                callback(xmlHttp.responseText);
            }
            else
            {
                alert('Hiba. : '+xmlHttp.statusText);
            }
        }
    }
    
    xmlHttp.open("POST",url);
    xmlHttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
    xmlHttp.send(params);
}

function jsonRequest(url,params,callback)
{
	request(url,params,function(content)
	{
		var obj=eval('('+content+')');
		callback(obj);
	});
}

function sendForm(obj,url,callback)
{
	var params='';
	
	var fields=new Array('input','textarrea','option');
	
	for(var j=0; j<fields.length; j++)
	{
		var elements=obj.getElementsByTagName(fields[j]);
		for(var i=0; i<elements.length; i++)
		{
			params+='&'+elements[i].name+'='+elements[i].value;
		}
	}
	
	if(params=='')
	{
		params=null;
	}
	else
	{
		params=params.substr(1);
	}
	
	request(url,params,callback);
	return false;
}

function display(id)
{
    var obj=document.getElementById(id);
    if(obj.style.display=='none')
    {
	obj.style.display='block';
    }
    else
    {
	obj.style.display='none';
    }
}