The source code

    /**
     * @ignore
     * simple menuitem render
     * @author yiminghe@gmail.com
     */
    KISSY.add("menu/menuitem-render", function (S, Node, Component, undefined) {

        var CHECK_CLS = "menuitem-checkbox";

        function setUpCheckEl(self) {
            var el = self.get("el"),
                prefixCls = self.get('prefixCls'),
                checkEl = el.one("." + prefixCls + CHECK_CLS);
            if (!checkEl) {
                checkEl = new Node("<div class='" + prefixCls + CHECK_CLS + "'/>")
                    .prependTo(el);
                // if not ie will lose focus when click
                checkEl.unselectable(/**
                 @type HTMLElement
                 @ignore
                 */undefined);
            }
            return checkEl;
        }

        return Component.Render.extend({

            _onSetChecked: function (v) {
                var self = this,
                    el = self.get("el"),
                    cls = self.getCssClassWithState("-checked");
                el[v ? 'addClass' : 'removeClass'](cls);
            },

            _onSetSelected: function (v) {
                var self = this,
                    el = self.get("el"),
                    cls = self.getCssClassWithState("-selected");
                el[v ? 'addClass' : 'removeClass'](cls);
            },

            '_onSetSelectable': function (v) {
                this.get("el").attr("role", v ? 'menuitemradio' : 'menuitem');
            },

            '_onSetCheckable': function (v) {
                if (v) {
                    setUpCheckEl(this);
                }
                this.get("el").attr("role", v ? 'menuitemcheckbox' : 'menuitem');
            },

            containsElement: function (element) {
                var el = this.get("el");
                return el && ( el[0] == element || el.contains(element));
            }
        }, {
            ATTRS: {
                checkable: {},
                elAttrs: {
                    valueFn: function () {
                        return {
                            role: "menuitem",
                            id: S.guid("ks-menuitem")
                        };
                    }
                },
                selected: {},
                // @inheritedDoc
                // content:{},
                // 属性必须声明，否则无法和 _onSetChecked 绑定在一起
                checked: {}
            },
            HTML_PARSER: {
                selectable: function (el) {
                    var cls = this.getCssClassWithPrefix("menuitem-selectable");
                    return el.hasClass(cls);
                },
                checkable: function (el) {
                    var cls = this.getCssClassWithPrefix("menuitem-checkable");
                    return el.hasClass(cls);
                }
            }
        });
    }, {
        requires: ['node', 'component/base']
    });