function pop_noscroll(ventana,altura,anchura)
{
	y=(screen.height/2) - (altura/2);
	x=(screen.width/2) - (anchura/2);
	parametros="toolbar=no,location=no,directories=no,titlebar=no,status=no,menubar=no,scrollbars=yes,resizable=no,copyhistory=no,width="+anchura+",height="+altura+",top="+y+",left="+x;
	miventana = window.open(ventana,"ventana",parametros);
}