jquery ajax async true no value displayd

I have a call to a method via ajax async:true, but the returned value is not displayed.

$('.loading').show();
 $.ajax({
        type: "POST",
        url: "/client/owedasync/",
        data: "client="+id,
        async: true,
        success: function(t){
            alert(t);
           $('.loading').hide();
           $("#sum_worhhoursowed").html(t+" hours owed");
        }
    });  

if changed to false, it will display the value. in firebug i can see the response value but not on the page when async: tru开发者_如何学编程e.

Uh, sorry. It works, but i used FF4b for testing and firebug 1.6x.0b3 with known problems with ajax & FF4b. Disabled the Console everything is back to normal.