if (Drupal.jsEnabled) {
  Drupal.behaviors.better_exposed_filters = function() {

    /*
     * Add Select all/none links to specified checkboxes
     */
    
    // Check for selected that already has the select all/none element for pages with outside ajaxy
    // things going on.
    var selected = $('.form-checkboxes.bef-select-all-none:not(.bef-processed)');
    if (selected.length) {
      var selAll = Drupal.t('Select All');
      var selNone = Drupal.t('Select None');
      
      // Set up a prototype link and event handlers
      var link = $('<a class="bef-toggle" href="#">'+ selAll +'</a>');
      link.click(function() {
        if (selAll == $(this).text()) {
          // Select all the checkboxes
          $(this)
            .html(selNone)
            .siblings('.bef-checkboxes')
              .find('.form-item input:checkbox').each(function() {
                $(this).attr('checked', 'checked');
              })
            .end()

            // attr() doesn't trigger a change event, so we do it ourselves. But just on 
            // one checkbox otherwise we have many spinning cursors
            .find('input[@type=checkbox]:first').change() 
          ;
        }
        else {
          // Unselect all the checkboxes
          $(this)
            .html(selAll)
            .siblings('.bef-checkboxes')
              .find('.form-item input:checkbox').each(function() {
                $(this).attr('checked', '');
              })
            .end()

            // attr() doesn't trigger a change event, so we do it ourselves. But just on 
            // one checkbox otherwise we have many spinning cursors
            .find('input[@type=checkbox]:first').change() 
          ;
        }
        return false;
      });

      // Add Select all/none link to the page for each set of checkboxes.
      selected
        .addClass('bef-processed')
        .each(function(index) {
          // Clone the link prototype and insert into the DOM
          var newLink = link.clone(true);
          
          newLink.insertBefore($('.bef-checkboxes', this));
          
          // If all checkboxes are already checked by default then switch to Select None
          if ($('input:checkbox:checked', this).length == $('input:checkbox', this).length) {
            newLink.click();
          }
        });
    }
    
    // Add highlight class to checked checkboxes for better theming
    $('.bef-tree input[type="checkbox"], .bef-checkboxes input[type="checkbox"]')
      // Highlight newly selected checkboxes
      .click(function() {
        this.checked
          ? $(this).parent().addClass('highlight')
          : $(this).parent().removeClass('highlight');
      })
      // Highlight ones that are checked on page load
      .filter(':checked').parent().addClass('highlight')
    ;
  };
}