$("#exam").siblings(".layui-form-select").find("dl").remove();

或

        layuiSelectDisable($("#exam")); // 设置selet元素不可下拉选择function layuiSelectDisable(selectElem) {try {var dlElem = selectElem.siblings(".layui-form-select").find("dl");if (dlElem != null) dlElem.remove()} catch (ex) { }}