AutoComplete Textbox Jquery

 $("#"+textbox).autocomplete({
            source: function (request, response) {
                $.ajax({
                    type: "POST",
                    contentType: "application/json; charset=utf-8",
                    url: "getMimicSecurityList",
                    data: "{'value':'" + elem + "'}",
                    dataType: "json",
                    success: function (data) {                
                        response($.map(data, function (item) {
                            return { label: item, value: item }}))
                    },
                    error: function (result) {
                        alert("No result found");
                    }
                });
            }
        });