var win = null;
	function winopen(datei,w,h,fenster){
		if (win != null){
		 if(win.closed == false){
		 	win.window.close();
			}
		}
		LeftPosition = (screen.width-w)/2;
		if (screen.height==600){
		TopPosition = 0
		}
		else{
		TopPosition = (screen.height-h)/4;
		}
	    settings ='height='+h+',width='+w+',top='+TopPosition+',left='+LeftPosition+',resizable=no';
	    win = window.open(datei, fenster, settings);
	    if(win.window.focus){win.window.focus();}
	    }