Focus on AutoComplete in JQuery Not working ?

<script type="text/javascript" language="javascript">
        $(function () {
            $('#<%=txtKeyWord.ClientID %>').autocomplete({
                source: function (request, response) {
                    $.ajax({
                        url: "WebService.asmx/spGetKeyword",
                        data: "{ 'keyword': '" + request.term + "' }",
                        type: "POST",
                        dataType: "json",
                        contentType: "application/json;charset=utf-8",
                        success: function (result) {
                            response(result.d);
                        },
                        error: function (result) {
                            alert('There is a problem processing your request');
                        }
                    });
                },
                minLength: 0,
                focus: function () {
                    $.ajax({
                        type: "POST",
                        contentType: "application/json; charset=utf-8",
                        data: "{ Iid: '" + $('#<%=txtItemCode.ClientID %>').val() + "'}",
                        url: "WebService.asmx/GetNameFromService",
                        dataType: "json",
                        success: function (data) {
                            $('#<%=txtKeyWord.ClientID %>').val(data.d);
                        }
                    });

                }
            });
        });

    </script>