[jQuery] ajax form post help needed

[jQuery] ajax form post help needed


I am using the ajax form plugin....working GREAT however I need to add
a loading grapic to display while it does the post. I have a div
(loader) thats just waiting to turn on and off but I can't get it to
show...any help would be great!!
code:
$(document).ready(function(){
            $('#chk_area').ajaxForm(function(service_return) {
                if (jQuery.trim(service_return)==1){
                     alert("Thank you for your comment! - 1");
                }
                else if (jQuery.trim(service_return)==0){
                    alert("Thank you for your comment! - 0");
                }
            });
        });