function desplegar(obj)
{
    //alert (obj);
    //alert($("#"+obj).css("display"));
    if ($("#subdiv_"+obj).css("display")=="none")
    {
        $("#subdiv_"+obj).slideDown("slow");
        $("#desplegable_"+obj).css("background","url('http://www.dochan.com/module/listadoanunciantes/static/image/arrow-up.png') no-repeat scroll right top transparent");
    }
    else if ($("#subdiv_"+obj).css("display")=="block")
        {
             $("#subdiv_"+obj).slideUp("slow");
             $("#desplegable_"+obj).css("background","url('http://www.dochan.com/module/listadoanunciantes/static/image/arrow-down.png') no-repeat scroll right top transparent");
        }
}