var btkModule = false;

function openJustPlayGame() {
    if (!btkModule) {
	  var hoehe = 768;
	  var breite = 1024;
	  if (screen.width < 1024) {
	  	hoehe = screen.height;
		  breite = screen.width;
	  }
      var links = (screen.width/2)-(breite/2);
      var oben = (screen.height/2)-(hoehe/2);
      btkModule = window.open("index.php?id=9","BEATTHEKING","height="+hoehe+",width="+breite+",status = no,toolbar = no,menubar = no,location = no,resizable = no,titlebar = no,scrollbars = yes,fullscreen = no,top ="+oben+",left ="+links);
    }
    else {
      alert ("Du hast schon ein JustPlayAGame Fenster offen!");
    }
}
function closeJustPlayGame () {
  btkModule = false;
}