var of = 0;

function PopUp(was,b,h) {

//Ist Fenster offen?
if (of == 1){
   pop.close();
   of=0;
}
//Öffne Fenster mit Inhalt
 pop = window.open(was,"MusicAdventure","toolbar=0,location=0,directories=0,status=0,menuebar=0,scrollbars=yes,resizable=0,width="+b+",height="+h+"");
 of=1;
}