var pop = null;

function ref_popup(datei,h) {
	if (pop != null) {
         	pop.close();
            }
	var eigenschaften="top=20, left=60, width=480, height="+h+", resizeable=no, status=no, scrollbars=no";
         var datei="content/referenzen/" +datei;
         pop = window.open(datei,'Referenzen',eigenschaften);
}