langs.reduce = [].reduce; // 给jQuery对象添加reduce方法!!
            function labelAllSelectState(flag) {
                if (flag) {
                    selectAllLabel.hide();
                    deselectAllLabel.show();
                } else {
                    selectAllLabel.show();
                    deselectAllLabel.hide();
                }
            }

            selectAll.change(function (event) {
                let checked = selectAll.is(':checked');
                labelAllSelectState(checked);
                langs.prop('checked', checked);
                log(event, checked);
            });
            invertSelect.click(function (event) {
                langs.map(function (i, ele) {
                    ele.checked = !ele.checked;
                });
                langs.change();
            });
            langs.change(function (event) {
                let allChecked = langs.reduce(function (value, item) {
                    return value && item.checked;
                }, true);
                labelAllSelectState(allChecked);
                selectAll.prop('checked', allChecked);
                log(this);
            })