Jquery UI.Combobox via UI.Autocomplete

gistfile1.js

    $.widget("ui.combobox", {
        _create: function() {
            var input,
                self = this,
                select = this.element.hide(),
                selected = select.find(":selected"),
                value = selected.val() ? selected.text() : "",
                wrapper = this.wrapper = $("<span>").addClass("ui-combobox").insertAfter(select);
            input = $("<input>")
                .appendTo(wrapper)
                .width(this.element.width())
                .val(value)
                .addClass("ui-state-default ui-combobox-input")
                .autocomplete({
                    delay: 0,
                    minLength: 0,
                    source: function(request, response) {
                        var matcher = new RegExp($.ui.autocomplete.escapeRegex(request.term), "i");
                        response(select.find("option").map(function() {
                            var self = $(this);
                            var text = self.text();
                            if (this.value && (!request.term || matcher.test(text)))
                                return {
                                    label: text.replace(
                                        new RegExp(
                                            "(?![^&;]+;)(?!<[^<>]*)(" +
                                            $.ui.autocomplete.escapeRegex(request.term) +
                                            ")(?![^<>]*>)(?![^&;]+;)", "gi"
                                       ), "$1"),
                                    value: text,
                                    group: self.parent("optgroup").attr("label"),
                                    option: this
                                };
                        }));
                    },
                    select: function(event, ui) {
                        ui.item.option.selected = true;
                        self._trigger("selected", event, {
                            item: ui.item.option
                        });
                        self.element.trigger("change");
                    },
                    change: function(event, ui) {
                        if (!ui.item) {
                            var matcher = new RegExp("^" + $.ui.autocomplete.escapeRegex($(this).val()) + "$", "i"),
                                valid = false;
                            select.find("option").each(function() {
                                if ($(this).text().match(matcher)) {
                                    this.selected = valid = true;
                                    return false;
                                }
                            });
                            if (!valid) {
                                $(this).val("");
                                select.val("");
                                input.data("autocomplete").term = "";
                                return false;
                            }
                        }
                    },
                    open: function(event, ui) {
                        input.data("toggle").addClass("ui-state-active");
                    },
                    close: function(event, ui) {
                        input.data("toggle").removeClass("ui-state-active");
                    }
                })
                .addClass("ui-widget ui-widget-content ui-corner-left");

            input.bind("blur", function() { 
                if ($(this).val() == "") {
                    input.data("autocomplete").element.val("");
                }
            });

            this.input = input;

            input.data("autocomplete")._renderItem = function(ul, item) {
                return $("<li></li>")
                    .data("item.autocomplete", item)
                    .append("<a>" + htmlentities(item.label) + "</a>")
                    .appendTo(ul);
            };

            input.data("autocomplete")._renderMenu = function(ul, items ) {
                var self = this;
                var group = null;
                $.each(items, function(index, item ) {
                    if (item.group && group != item.group) {
                        $("<li></li>").append("<b>" + htmlentities(item.group) + "</b>").appendTo(ul);
                    }
                    self._renderItem(ul, item );
                    group = item.group;
                });
            };

            input.data("toggle", $("<a>")
                .attr("tabIndex", -1)
                .appendTo(wrapper)
                .addClass("ui-icon-triangle-1-s ui-combobox-toggle ui-icon ui-state-default ui-corner-all")
                .click(function() {
                    if (input.autocomplete("widget").is(":visible")) {
                        input.autocomplete("close");
                        return;
                    }
                    $(this).blur();
                    input.autocomplete("search", "");
                    input.focus();
                }));
        },

        destroy: function() {
            this.wrapper.remove();
            this.element.show();
            $.Widget.prototype.destroy.call(this);
        }
    });