function abrir(htmlfile, wndWidth, wndHeight) {
  var popWnd;  //Objeto ventana de popup
  var maxWidth = screen.width-10;
  var maxHeight = screen.height-56;

  //Preprocesado de parámetros
  if (wndHeight==0) wndHeight = maxHeight;
  if (wndWidth==0) wndWidth = maxWidth;

  //Calculo de la posición para centrar la ventana
  var posX = maxWidth/2 - wndWidth/2;
  var posY = maxHeight/2 - wndHeight;

  //Postprocesado de la coordenada horizontal para mas de 800x600
  if(maxWidth >= 800) posX = -10;

  //Ventana
  if (popWnd) popWnd.close();
  popWnd = open(htmlfile, '_blank', 'resizable=1,toolbar=0,scrollbars=0,location=0,directories=0,status=0,menubar=0,width='+wndWidth+',height='+wndHeight+',screenX=0,screenY=0,left='+posX+',top='+posY);

  //this.blur();
  popWnd.focus();
}