Drupal behaviour function not getting executed

I defined a simple block on my module, using the following code.

function visita_virtual_block_view($delta = '') {
  switch ($delta) {
    case 'mapa':
      $path = drupal_get_path('module','visita_virtual');
      drupal_add_js('https://maps.google.com/maps/api/js?sensor=false','external');
      drupal_add_js($path.'/visitavirtual.js');
      $block['subject'] = t('google maps');
      $block['content'] = visita_virtual_mapa_content();
      return $block;
  }
}

That returns a simple div with an specific id, wich will allow me to alter it later through the usage of the google maps api. For that I defined my 'visitavirtual.js' file, and inside of it I declared the Drupal behavior. That function is supposed to get executed when the whole page is loaded, since it'as a wrapper of the JQuery ready function.

(function($){
  Drupal.behaviours.visita_virtual = {
    attach: function(context,settings) {
      alert('Entered the init function');
      var latlng = new google.maps.LatLng(-34.397, 150.644);
      var myOptions = {
        zoom: 8,
        center: latlng,
        mapTypeId: google.maps.MapTypeId.ROADMAP
      };

      var map = new google.maps.Map(document.getElementById("map_canvas"),myOptions);
    }
  };
})(JQuery);

However, that code is not executed; I can't even see the alert window. What am I doing wrong?