var tracking_pic = new Array();
    tracking_pic[0]=new Image();
    tracking_pic[0].src='/public/images/trombone_inactive.png';
    tracking_pic[1]=new Image();
    tracking_pic[1].src='/public/images/trombone_active.png';
    tracking_pic[2]=new Image();
    tracking_pic[2].src='/public/images/trombone_selected.png';
 
    function tracking_showdyn(action,id)
    {
      document.getElementById('tracking_img_'+action+'_'+id).src=tracking_pic[1].src;
    }

    function tracking_showdynout(action,id)
    {
      document.getElementById('tracking_img_'+action+'_'+id).src=(document.getElementById('tracking_'+action+'_'+id).value>0)?tracking_pic[2].src:tracking_pic[0].src;
    }

    function tracking_validate(action,id)
    {
      var selected;

      if (document.getElementById('tracking_'+action+'_'+id).value != 0)
        selected = 0;
      else
        selected = 1;

      document.getElementById('tracking_img_'+action+'_'+id).src=(selected>0)?tracking_pic[2].src:tracking_pic[0].src;
      document.getElementById('tracking_'+action+'_'+id).value = selected;

      var request = new Ajax.Request(
                      '/ajax/'+action,
                      {
                        method:       'get',
                        parameters:   'id='+id+'&selected='+selected,
                        asynchronous: true
                      }
                    );

    }