function open_attributes( id, id_toggle) {
    if( $(id).style.display == 'none') {
      new Effect.Appear( id, {duration: .3});
      new Effect.BlindDown( id, {duration: .3});
      $(id_toggle).className = 'open'
    }
    else {
      new Effect.Fade( id, {duration: .3});
      new Effect.BlindUp( id, {duration: .3});
      $(id_toggle).className = 'close'
    }
  }
  
  var ToggleSelect = Class.create();

  ToggleSelect.prototype = {

    initialize: function (id_select, options) {
                  this.id_select = id_select;
                  this._options = options;
                  Event.observe (this.id_select, 'change', this.actua.bindAsEventListener (this), true);
                  this.actua ();
              },

    actua:      function (e) {
                var seleccionada = $F(this.id_select);
                for (var a = 0 ; a < this._options.length ; a++)
                {
                  style = this._options[a][0] == seleccionada ? 'block' : 'none';
                  class_name = this._options[a][0] == seleccionada ? 'required' : '';
                  if ($(this._options[a][1])) {
                    $(this._options[a][1]).style.display = style; 
                    if( $(this._options[a][1] + '_select'))
                      $(this._options[a][1] + '_select').className = class_name
                    var quants = $$('.' + this._options[a][1] + '_quantity');
                    if( quants.length > 0 ) {
                      var quantities = $$('._quantity');
                      for (var i=0; i < quantities.length; i++) {
                        Element.removeClassName( quantities[i], 'required validate-digits');
                      };
                    }
                    for (var i=0; i < quants.length; i++) {
                      Element.addClassName( quants[i], 'required validate-digits');
                    };
                  }
                    
                }
              }
  };
  
  function openWindow(url,name,width,height) {
    window.open(url,name,"menubar=1,resizable=1,scrollbars=yes,width=" + width + ",height=" + height);
  }