Zend FR

            if($validator instanceof Zend_Validate_StringLength)
            {
                $params['rules']['rangelength'] = array($validator->getMin(), $validator->getMax());
            }
            else if($validator instanceof Zend_Validate_Digits )
            {
                $params['rules']['digits'] = true;
            }
            else if($validator instanceof Zend_Validate_EmailAddress )
            {
                $params['rules']['email'] = true;
            }

$form->addElement('text', 'nom',  array(
    'validators' => array(
        array( 'stringLength', false, array( 1, 45 )),
        array('AccountNotExists', false, array( $this->id ))
        ),
    'required' => true,
    'label' => 'Nom',
    'size' => 45,
    'prefixPath' => array( Zend_Form_Element::VALIDATE  => array('prefix' => 'Freeh_Validate', 'path' => 'Freeh/Validate')),
    'jQueryFormValidators' => array(
        'rules' => array('remote' => '/account/validate/account/account_type/' . $this->id),
        'messages' => array('remote' => utf8_encode('Ce nom est déjà pris'))
        ),
    ));

$form = new Zend_Form(...);
$form->addElements(...);
$options = array('onkeyup' => false,);
Freeh_JQuery::addClientValidation($form, $options);
$this->view->form = $form;

class Freeh_JQuery_Form_Decorator_Validator extends Zend_Form_Decorator_Abstract
{
    public function __construct($options = null){ $this->params = $options; }

    protected $params = array();

    public function render($content)
    {
        $element = $this->getElement();
        
        if($element instanceof Zend_Form)
        {
            if(count($this->params) > 0) {
            require_once "Zend/Json.php";
            $params = Zend_Json::encode($this->params);
            } else {
                $params = "{}";
            }

            $js = sprintf('%s("#%s").validate(%s);',
                ZendX_JQuery_View_Helper_JQuery::getJQueryHandler(),
                $element->getId(),
                $params
            );
            $element->getView()->JQuery()->addOnLoad($js);
        }
        if($element instanceof Zend_Form_DisplayGroup){ } // todo ??
        
        if($element instanceof Zend_Form_Element)
        {
            $this->extractParams($element); // extrait les paramètres et remplit $this->params;
        }
        
        return $content;
    }
    
    protected function extractParams(Zend_Form_Element $element)
    {
        $params = $element->getAttrib('jQueryFormValidators');
        
        if(!is_array($params))
            $params = array();

        if($element->isRequired())
        {
            $params['rules']['required'] = true;
        }
        foreach($element->getValidators() as $validator)
        {
            if($validator instanceof Zend_Validate_StringLength)
            {
                $params['rules']['rangelength'] = array($validator->getMin(), $validator->getMax());
            }
            else if($validator instanceof Zend_Validate_Digits )
            {
                $params['rules']['digits'] = true;
            }
            else if($validator instanceof Zend_Validate_EmailAddress )
            {
                $params['rules']['email'] = true;
            }
        }
        
        if(count($params) > 0) 
        {
            $this->params['rules'][$element->getName()] = isset($params['rules']) ? $params['rules'] : array();
            if(isset($params['messages']))
                $this->params['messages'][$element->getName()] = $params['messages'];
        }
        
        $element->setAttrib('jQueryFormValidators', null);
    }
}

<?php

class Freeh_JQuery
{
    
    public static function addClientValidation(Zend_Form $form, $options = null)
    {
        $form->addPrefixPath('Freeh_JQuery_Form_Decorator', 'Freeh/JQuery/Form/Decorator', 'decorator')
             ->addElementPrefixPath('Freeh_JQuery_Form_Decorator', 'Freeh/JQuery/Form/Decorator', 'decorator')
             ->addDisplayGroupPrefixPath('Freeh_JQuery_Form_Decorator', 'Freeh/JQuery/Form/Decorator');

        $jqueryValidator = new Freeh_JQuery_Form_Decorator_Validator($options);
        $form->addDecorator($jqueryValidator); // rendu à la fin
        
        $form->getView()->jQuery()
            ->addJavascriptFile('/js/jquery.validate.min.js')
            ->addJavascriptFile('/js/localization/messages_fr.js');
        
        
        // passe sur tout les items pour ajouter le decorateur en premier
        // ne doit pas marcher avec les subform et autres Zend_Element particulier.
        // Je n'ai pas d'exemple pour tester et trouver une solution le cas où ça ne marcherait pas.
        foreach ($form as $item) {
            $olds = $item->getDecorators();
            $item->clearDecorators();
            $item->addDecorator($jqueryValidator);
            $item->addDecorators($olds);
        }
    }
}

// utilisé dans la vue : <?= $this->JQueryFormValidation($this->form, array('onkeyup' => false)) ?>
// ou $form est un Zend_Form classique dans lequel on aura pris soin d'ajouter des éléments et leur validateur
class Freeh_View_Helper_JQueryFormValidation extends Zend_View_Helper_Abstract
{
    public function JQueryFormValidation(Zend_Form $form, array $options = null)
    {
            Freeh_JQuery::addClientValidation($form, $options);
        return $form;
    }
}