Activate client side validation for a dynamic (ajax) created form JS error

@Jelle_S, thanks for the answer, youre totally right..

I'll try to convert my code in "drupal style"

After Jelle_S answer, i tryed to use the Drupal ajax framework to load the form, and I guess I found a bug in clientside validation: when I load the form via ajax, I always get the error "TypeError: j is undefined" in jquery.js?v=1.4.4 (row 33).

Thats happen just after the loading of clientside_validation.js: http://imgur.com/TwqvSmJ

I also tryed to load manually the clientside_validation js in the page, but I get the same error (perhaps somethig needs to be initialized before load them?)

If i disable clientside_validation modules (currently im using fapi and form submodules) the ajax workflow works perfetcly.

This is the simpliest code to reproduce the error:

function mymodule_menu(){
  return array(
    // Standard drupal page rendering a form. As callback, im not udin drupal_get_form directly
    // becose i'll have to do some extra manipulation before render the form.
    'mymodule/form' => array(
      'page callback' => 'mymodule_create_form',
      'access callback' => true
    ),
    // Empty page that
    'mymodule/ajax' => array(
      'page callback' => 'mymodule_ajax_page',
      'access callback' => true
    ),
    'mymodule/ajax/form' => array(
      'delivery callback' => 'ajax_deliver',
      'page callback' => 'mymodule_ajax',
      'access callback' => true,
      'page arguments' => array(2)
    ),
  );
}
/**/

// Return a simple markup, with an ajax element to load the form.
function mymodule_ajax_page(){
  // I also tryed to load manually the clientside validation JS, but I got the same error.
/*
  drupal_add_js(drupal_get_path('module', 'clientside_validation') . '/jquery-validate/jquery.validate.js');
  drupal_add_js(
    drupal_get_path('module', 'clientside_validation') . '/clientside_validation.ie8.js',
    array('scope' => 'footer')
  );
  drupal_add_js(
    drupal_get_path('module', 'clientside_validation') . '/clientside_validation.js',
    array('scope' => 'footer')
  );
*/

  return array(
    '#type' => '#markup',
    '#suffix' => 'suffisso<div id="the-form-here"></div>',
    'links' => array(
      'form-link-load' => array(
        '#type' => 'link',
        '#href' => 'mymodule/ajax/form',
        '#title' => 'Click to load the form!',
        '#ajax' => array(
          'event' => 'click',
          'callback' => 'mymodule_ajax'
        )
      )

    )
  );
}

function mymodule_ajax(){
  $form = drupal_get_form('mymodule_form_test');
  $html = drupal_render($form);
  $commands = array();
  $commands[] = ajax_command_insert('#the-form-here', $html);
  return array('#type' => 'ajax', '#commands' => $commands);
}

/**/
function mymodule_create_form($vals = null){
  $form = drupal_get_form('mymodule_form_test');
  $html = drupal_render($form);
  return $html;
}
/**/


// Create the form
function mymodule_form_test($form, $form_state) {
  $form['field_a'] = array(
    '#type' => 'textfield',
    '#title' => t('Normal validation, required'),
    '#default_value' => '',
    '#size' => 60,
    '#maxlength' => 128,
    '#required' => TRUE,
  );

  $form['field_b'] = array(
    '#type' => 'textfield',
    '#title' => t('Clientside validation, 5-8 chars'),
    '#default_value' => '',
    '#size' => 60,
    '#maxlength' => 128,
    '#rules' => array(
      'length[5, 8]',
    )
  );

  $form['send'] = array(
    '#type' => 'submit',
    "#value" => "SEND THIS TEST",
  );

  return $form;
}
/**/

Jelle_S, i'll try tomorrow and tell if it works ;)

Jelle_S ys, just tryed and now works, sorry but i've been very busy