function otworzPopUp(url, w, h){
	var okno=null; 
    if (okno){ 
        okno.close(); 
    } 
    okno = window.open(url,'','width=' + w + ',height=' + h + ',top=' + (screen.height/2 - h/2) + ',left=' + (screen.width/2 - w/2) + ',scrollbars=no, location=no, directories=no, status=no, menubar=no, toolbar=no, resizable=no'); 
    okno.focus(); 
}