function popup(n,height,width)
	{
		var window_height = height;
		var window_width = width;

		var screen_l = screen.width / 3;
		var screen_t = screen.height / 3;

		screen_l = (screen_l - (window_width / 3));
		screen_t = (screen_t - (window_height / 3)) - 10;

		welke = n;
		var options = 'width=' + window_width + ',height=' + window_height + ',left=' + screen_l + ',Top=' + screen_t + ',toolbar=0,menubar=0,location=0,scrollbars=0,directories=0,status=0,resizable=0'
		window.open( welke, 'popup' ,options ) ;
	}