var RicercaMotoForm = new Class({

  initialize: function(form, errorMessage) {
    this.form = $(form).addEvent('submit', this.handleSubmit.bindWithEvent(this));
    this.errorMessage = errorMessage;
    this.selects = [ 'marca', 'modello', 'cc' ].map(function(name) {
      return this.form.getElement('select[name=' + name + ']')
    }, this);
  },

  handleSubmit: function(e) {
    var valid = true;
    this.selects.each(function(select) {
      var v = select.get('value');
      select[v == '' ? 'addClass' : 'removeClass']('error');
      valid = valid && (v != '');
    });
    if (!valid) {
      alert(this.errorMessage);
      e.stop();
    }
  }

});