function exportValues($elementList = null)
    {
        $values = array();
        if (null === $elementList) {
            // iterate over all elements, calling their exportValue() methods
            foreach (array_keys($this->_elements) as $key) {
                $value = $this->_elements[$key]->exportValue($this->_submitValues, true);
                if (is_array($value)) {
                    // This shit throws a bogus warning in PHP 4.3.x
                    $values = HTML_QuickForm::arrayMerge($values, $value);
                }
            }
        } else {
            if (!is_array($elementList)) {
                $elementList = array_map('trim', explode(',', $elementList));
            }
            foreach ($elementList as $elementName) {
                $value = $this->exportValue($elementName);
                $pear = new PEAR();
                if ($pear->isError($value)) {
                    return $value;
                }
                $values[$elementName] = $value;
            }
        }
        return $values;
    }