JQuery : Autocomplete Force Input

case : you use jquery autocomplete to replace an old style drop down menu and you want to force user to choose at least one of these input option.
solution : use a "mustMatch";

        $().ready(function() {
            $("#kategori").autocomplete("../actions/autocomplete.php?p=kategori", {
                width: 190,
                max: 2000,
                selectFirst: false,
                mustMatch:true,
            });
        });