function openWin(url,breite,hoehe,windowName){	
	if (window.itsWindow && !(itsWindow.closed)){
	    itsWindow.focus();
	    itsWindow.location.href=url;
	    return false;
	} else {
		params = "toolbar=no,status=no,location=no,scrollbars=yes,menubar=no,width=" + breite + ",height=" + hoehe + ",screenX=0,screenY=0,top=0,left=0";
		itsWindow = open(url, "MainFenster", params);
		itsWindow.focus();
	}			
}