#process callback for #pattern form element property.
$element: An associative array containing the properties and children of the generic input element.
$form_state: The $form_state array for the form this element belongs to.
The processed element.
function form_process_pattern($element, &$form_state) {
if (isset($element['#pattern']) && !isset($element['#attributes']['pattern'])) {
$element['#attributes']['pattern'] = $element['#pattern'];
$element['#element_validate'][] = 'form_validate_pattern';
}
return $element;
}