The source code

    /**
     * @ignore
     *  Single tab render in tab bar.
     * @author yiminghe@gmail.com
     */
    KISSY.add("tabs/tab-render", function (S, Button) {

        return Button.Render.extend({
            createDom: function () {
                this.get("el").attr("role", "tab");
            },
            _onSetSelected: function (v) {
                var el = this.get("el");
                el[v ? 'addClass' : 'removeClass'](this.get("selectedCls"));
                el.attr('aria-selected', !!v);
            }
        }, {
            ATTRS: {
                selected: {
                    value: false
                },
                selectedCls: {
                    valueFn:function(){
                        return this.get('prefixCls')+'tabs-tab-selected';
                    }
                }
            },
            HTML_PARSER: {
                selected: function (el) {
                    return el.hasClass(this.get("selectedCls"));
                }
            }
        });

    }, {
        requires: ['button']
    });