var activities = new Array();

  activities.push(new Array($R(4,6), 'Moussaillon', 'mous'));

  activities.push(new Array($R(7,10), 'Optimist', 'opti'));

  activities.push(new Array($R(8,11), 'Funboat', 'funb'));

  activities.push(new Array($R(10,18), 'Pico', 'pico'));

  activities.push(new Array($R(12,16), 'Topaz', 'topa'));

  activities.push(new Array($R(14,18), 'Dart 16', 'dart'));

  activities.push(new Array($R(12,18), 'Planche à Voile', 'pav'));

  activities.push(new Array($R(15,18), 'First Class 8', 'class'));

  activities.push(new Array($R(16,18), 'Cata perf', 'catp'));

  activities.push(new Array($R(14,17), 'First 31,7', 'f317j'));

  activities.push(new Array($R(18,18), 'First 31,7', 'f317s'));


function ageSelected() {
  age_value = $('search_age').getValue();
  options = $('search_activity').options;
  options.length = 1;
  activities.each(function(activity) {
    if (activity[0].include(age_value)) {
      options[options.length] = new Option(activity[1], activity[2]);
    }
  });
}

document.observe('dom:loaded', function() {
  $('search_age').observe('change', ageSelected);
});