if we have the form with being cloned on page with JS It is impossible to filter duplicates, empties, or validate them by count. Next code allows this. Like that: $filters=array( 'inp'=>'StripTags', 'inp_array'=>array('fields'=>'inp','array'=>true,'ArrEmptyItems','ArrDuplicates'); $validators=array( 'inp_array'=>array('fields'=>'cat','array'=>true,array('ArrCountBetween',1,10));

class Zend_Filter_Input2 extends Zend_Filter_Input {

protected function _filterRule(array $rule) {
    if(@$rule['array']) {
        $this->_data[$rule[self::FIELDS]]=array($this->_data[$rule[self::FIELDS]]);
        parent::_filterRule($rule);
        $this->_data[$rule[self::FIELDS]]=$this->_data[$rule[self::FIELDS]][0];
    } else
        parent::_filterRule($rule);
}

protected function _validateRule(array $rule) {
    if(@$rule['array']) {
        $this->_data[$rule[self::FIELDS]]=array($this->_data[$rule[self::FIELDS]]);
        parent::_validateRule($rule);
        $this->_validFields[$rule[self::FIELDS]]=$this->_validFields[$rule[self::FIELDS]][0];
    } else
        parent::_validateRule($rule);
}

}