function gui()
{	
	height = document.documentElement.clientHeight;
	height = height - 166;
	document.getElementById('navi').style.minHeight = height + 'px';
	
	document.getElementById('f_window').style.display = 'block';
	
	//alert("Width: " + document.documentElement.clientWidth + "\nHeight: " + document.documentElement.clientHeight);
}

var fenster = null;
function popup(doc, breite, hoehe)
{
  	if (breite == null)
	{
		breite = 580;
	}
  	if (hoehe == null)
	{
		hoehe = 540;
	}
	
	if (fenster==null || fenster.closed)
	{
		fenster=window.open(doc,"popup",'width='+ breite +',height='+ hoehe +',scrollbars=yes,toolbar=no,resizable=yes,directories=no,menubar=no,status=no,location=no');
		fenster.creator = self;      
	}
	else {
		fenster.location = doc;
		fenster.focus();
	}
	
}