function closePopUp()
{
  if(PopUpWindow && PopUpWindow.close) PopUpWindow.close();
}

function PopUp(fotka) 
{
	var popW = 700;
	var popH = 525;
	var popL = eval((screen.Width-popW)/2);
	var popT = eval((screen.Height-popH)/2);
    
    closePopUp();
    
    params = "width=" + popW+ ",height=" + popH + ",toolbar=no,location=no,directories=no,status=no,menubar=no,scrollbars=no" + ",resizable=no,left=" + popL + ",top=" + popT;
	pop='okno.php?f='+fotka;
	PopUpWindow = window.open(pop, 'PopUpWindow', params);
}