Edit in JSFiddle

(function() {
    var manufacturers = ['Volkswagen', 'Audi', 'Mercedes', 'Skoda', 'Toyota', 'Renault', 'Volvo', 'Mazda'];
    
    $("#list").autocomplete({
        source: manufacturers
    });

    // Overrides the default autocomplete filter function to search only from the beginning of the string
    $.ui.autocomplete.filter = function (array, term) {
        var matcher = new RegExp("^" + $.ui.autocomplete.escapeRegex(term), "i");
        return $.grep(array, function (value) {
            return matcher.test(value.label || value.value || value);
        });
    };
})();

<input type="text" id="list" />

input {
    margin: 10px;
}