function refresh_calendar(day)
   {
      var month = document.monthchooser.month.options[document.monthchooser.month.selectedIndex].value;
      var year = document.monthchooser.year.options[document.monthchooser.year.selectedIndex].value;
      var type = document.criteria.type.options[document.criteria.type.selectedIndex].value;
      var location = document.criteria.location.options[document.criteria.location.selectedIndex].value;
      var keywords = document.criteria.keywords.value;
      var past = document.criteria.past.checked;

      url = 'calendar.php?month=' + month + '&year=' + year;
      if (day != '' ) url = url + '&day=' + day;
      if (type != 'Any') url = url + '&type=' + type;
      if (location != 'Any') url = url + '&location=' + myencode(location);
      if (keywords != '' ) url = url + '&keywords=' + keywords;
      if (past == true) url = url + '&past=yes';

      window.location.href = url;
   }