function refresh() {
  var loc = "" + document.location;
  var idx = loc.indexOf( "?" );
  if( idx > 0 ) loc = loc.substring( 0, idx );
  idx = document.list_s.y.selectedIndex;
  window.location.replace( loc + 
    "?m=" + (document.list_s.m.selectedIndex + 1) +
    "&y=" +  document.list_s.y.options[idx].value );
}