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    '#process' => array('captcha_element_process'),

    // The type of challenge: e.g. 'default', 'none', 'captcha/Math', 'image_captcha/Image'.

    '#captcha_type' => 'default',

    '#default_value' => '',

    // CAPTCHA in admin mode: presolve the CAPTCHA and always show it (despite previous successful responses).

    '#captcha_admin_mode' => FALSE,

  module_load_include('inc', 'captcha');

  drupal_add_js(drupal_get_path('module', 'captcha') . '/captcha.js');

  // Prevent caching of the page with CAPTCHA elements.

  // This needs to be done even if the CAPTCHA will be ommitted later:

  // other untrusted users should not get a cached page when

  // the current untrusted user can skip the current CAPTCHA.

  // Get the form ID of the form we are currently processing (which is not

  // necessary the same form that is submitted (if any).

    'captcha_sid' => $captcha_sid,

  );

    // Generate a CAPTCHA and its solution

    // (note that the CAPTCHA session ID is given as third argument).

    $captcha = module_invoke($captcha_type_module, 'captcha', 'generate', $captcha_type_challenge, $captcha_sid);

 *     if the values could not be found, e.g. for a fresh form).

 */

function _captcha_get_posted_captcha_info($element, $form_state, $this_form_id) {

    // We are handling (or rebuilding) an already submitted form,

    // so we already determined the posted form ID and CAPTCHA session ID

    // for this form (from before submitting). Reuse this info.

  // of multi-page forms. Take previewing a node submission for example:

  // when the challenge is solved correctely on preview, the form is still

  // not completely submitted, but the CAPTCHA can be skipped.

    // Update captcha_sessions table: store the solution of the generated CAPTCHA.

    _captcha_update_captcha_session($captcha_sid, $captcha_info['solution']);