var effect_finished;
function publicacion_dom_loaded()
{
    effect_finished = false;
    
    $("form_cart").observe( 
        "submit",
        function(ev)
        {
            if ( effect_finished )
                return;
            
            var img_pos_rel = $("imagen_publicacion").viewportOffset();

            var img_pos = $("imagen_publicacion").viewportOffset();
            var cesta_pos = $("boton_iniciar_compra").viewportOffset();

            var delta_x = cesta_pos.left - img_pos.left + 80;
            var delta_y = cesta_pos.top - img_pos.top;

            var ip = $("imagen_publicacion");

            ip.style.position = "fixed";
            ip.style.left = img_pos_rel.left + "px";
            ip.style.top = img_pos_rel.top + "px";
            
            

            new Effect.Shrink( ip, {duration:1.5}  );
            new Effect.Move( ip, 
                             { x: delta_x, y: delta_y, duration: 1.5,
                               afterFinish: function() {
                                   effect_finished = true;
                                   $("form_cart").submit();
                               }
                             }); 

            ev.stop();
        });
}