function pop_page(pagina, width, height) {
//   var W = Math.min(width, 1024);
//   var H = Math.min(height, 700);
   var W = width;
   var H = height;
   if (W < 500) W = 500;
   if (H < 250) H = 250;
   var bigpic = window.open(pagina, 'page_window','toolbar=0,location=0,directories=0,status=0,menubar=0,scrollbars=1,resizable=1,copyhistory=0,width='+W+',height='+H+'');
   bigpic.focus();
}