[jQuery] problem with click event-IE needs to click where FF needs only one:

[Genia]

<script type="text/javascript">
        $(document).ready(function(){
        $("#pac").click(function(){
        $("#pac").animate({marginTop: "17px", paddingBottom: "17px",
borderBottom: "2px solid white"}, 2500 );
        $.post("rpc.php", {u:"genia"}, function(data){
                            if(data.length >0) {
           $("#pac_c").append(data);
                            }else{
                        $("#pac_c").css({overflow: "none", display: "none"});
                        }
                $("#pac_c").css({overflow: "auto", display: "block"});

        })});
        });
</script>

In FF the div animates and do the Post with only one click(like i
want) on IE i need to click twice for it to the POST too/

any help?