function openwindow(dateiname, fenstername, breite, hoehe){
					fenster = window.open(dateiname,fenstername,'location=0,toolbar=no,width=' + breite + ',height=' + hoehe + ',directories=no,scrollbars=auto,resize=yes,menubar=no,status=no');
					fenster_offen = "true";
					if ( parseInt(navigator.appVersion.substring(0,1)) >= 4 ){
						links = (screen.availWidth - parseInt(breite)) / 2;
						rechts = (screen.availHeight - parseInt(hoehe)) / 2;
						fenster.moveTo( links,rechts-30 );
						fenster.focus();
	
						if ((screen.availWidth - eval(breite)) <=30 ) { fenstername.screenX = 1 };
					};
								return;
				};