Contextual description of Captcha form

It seems a bit overkill to implement this in the CAPTCHA module itself. Unless a lot of people support this request, I'm flagging this thread as "won't fix".
Note that the description field handling is already complicated in a multilingual setup, where there is a description field for every language. If we add an extra dimension of description per context/form_id, things would get messy and there would not be enough room in the table.

I see two possible solutions for you:

1. On module level: implement it in a separate module. Implement a hook_form_alter(), look for CAPTCHA elements ($element['#type'] = 'captcha'), and change the '#description' field of the CAPTCHA element to what you want.
2. On theme level: override the theming of the CAPTCHA element, which is currently done as follows:
   

    /**
    * Theme function for a CAPTCHA element.
    *
    * Render it in a fieldset if a description of the CAPTCHA
    * is available. Render it as is otherwise.
    */
   function theme_captcha($element) {
     if (!empty($element['#description']) && isset($element['captcha_widgets'])) {
       $fieldset = array(
         '#type' => 'fieldset',
         '#title' => t('CAPTCHA'),
         '#description' => $element['#description'],
         '#children' => $element['#children'],
         '#attributes' => array('class' => 'captcha'),
       );
       return theme('fieldset', $fieldset);
     }
     else {
       return '<div class="captcha">'. $element['#children'] .'</div>';
     }
   }
   

   Here you can change the description too to whatever you like.

Both solutions require a certain level of coding skills and drupal development background, I don't know if this is feasible for you?

This is not the place to give you an introduction in Drupal development, but I can give you some clues.

The module you need is actually very simple. The trick is that you can add CAPTCHA's without the admin UI offered by the CAPTCHA module with just a bit of code (you still need the CAPTCHA module as a dependency for the CAPTCHA processing).

This is all you need to add a CAPTCHA (with custom description) to the user registration form: (disclaimer I didn't try this code, so there could be some quirks here or there)

/**
 * Implementation of hook_form_alter().
 */
function your_module_form_alter(&$form, $form_state, $form_id) {
  if ($form_id == 'user_register') {
    $form['captcha'] = array(
      '#type' = 'captcha',
      '#description' = t("Thanks for taking the time to register. This is the last time you'll ever have to answer this question!"),
    );
  } 
}

Make sure you don't set a CAPTCHA with the admin UI of the CAPTCHA module, as this could overwrite this custom CAPTCHA or add another CAPTCHA.

Please report how it turns out.

@colemanw : In your method:

1. How to change the Math type of CAPTHA to Image type of CAPTHA ?

2. How to remove the 'title' or '#description' field of the math(or image) CAPTCHA that say "Math question：Solve this simple math problem and enter the result. E.g. for 1+3, enter " . Note: not the top description that say "This checks that you are a real person and not a spam program.
Thanks for taking the time to register. This is the last time you'll ever have to answer this question!"

3. Why don't see the structures by devel.module's dprint_r() function?

Thank you very much!

1: see #743056: Document how to add a CAPTCHA programmatically
2 and 3: I don't understand your question

1. I mean removing the description of Image CAPTCHA, take a look at screenshot.
The screenshot is here: http://drupal.org/files/issues/remove_1.jpg

2. What does the my_captcha_element mean In the following code ? Replace the captcha/Math with what if using Image CAPTCHA?

$form['my_captcha_element'] = array(
  '#type' => 'captcha',
  '#captcha_type' => 'captcha/Math',
);

Thanks a lot!

The screenshot

@zhongguo999999:

To use the image captcha, use "#captcha_type": "image_captcha/Image" (the format is "$module/$type" with $module="image_captcha" and $type="Image")

Removing the description and title is not possible through (image) CAPTCHA settings, but possible solutions/workaround:
* CSS (which you don't want)
* something like http://drupal.org/project/stringoverrides
* custom form_altering as pointed out by colemanw in #10

@soxofaan
Thanks for your answer.

function mymenu_form_alter(&$form, $form_state, $form_id) {
$form['captcha'] = array(
#type' => 'captcha',
'#captcha_type' => 'image_captcha/Image',
}
The snippet works for me

* custom form_altering as pointed out by colemanw in #10
But the dpm(),dprint_r(),dsm() couldn't display the structure of the description（or title） on the following line(in screenshot), only display the structure of the description on the first line(in screenshot). So I couldn't alter the them.
* something like http://drupal.org/project/stringoverrides
I don't want use too many module, I want to wrint my custom module.
* CSS
I don't want to use.

How to remove it using alter? help me!

@colemanw, soxofaan: Thanks for your answer.

1. According to your method, It don't works, something must be wrong. help!

 $conf['form']['captcha_response'] = array( 
   '#title' => t('1111What code is in the image?'),
 );

2. I can alter the first line description on the screenshot, but couldn't alter the following line description on the screenshot. Something is wrong. Can someone give me help?

function mymenu_form_alter(&$form, $form_state, $form_id) {
      $form['captcha'] = array(
            #type' => 'captcha',
            '#captcha_type' => 'image_captcha/Image',
           '#children' => $element['#children'], //It display the following line description on the screenshot.
           '#description' => t('This question is for testing whether you are a human visitor and to prevent automated spam submissions.6666, I alter it'), //It works. I can alter the first line description in the screenshot.
           $form['captcha']['captcha_response']['#description'] =t('Enter the characters shown in the image.I couldn't alter it'), //It don't works. I couldn't alter the fllowing line description in the screenshot
        )
}

BTW: I don't want to hacking contrib modules, so I don't modify the code below. I just wanna override by using my custom module.

function image_captcha_captcha($op, $captcha_type='', $captcha_sid=NULL) {
...
$result['form']['captcha_response'] = array(
          '#type' => 'textfield',
          '#title' => t('What code is in the image?'), //you can modify it if you want hacking.
          '#description' => t('Enter the characters shown in the image.'),//you can modify it if you want hacking.
          '#weight' => 0,
          '#required' => TRUE,
          '#size' => 15,
...
}

OK，Thank you, but I think Drupal community is a good community college.

In your custom module, implement hook_captcha which calls image_captcha_captcha:

/**
 * Implementation of hook_captcha().
 */
function custommodule_captcha($op, $captcha_type='', $captcha_sid=NULL) {
	$result = image_captcha_captcha($op, $captcha_type, $captcha_sid);
	
	if($op == 'generate') {
		$result['form']['captcha_response']['#title'] = t('Code');
	}
	
	return $result;
}

After adding the hook, go to captcha admin settings and change the challenge type to that from your custom module.

It's not the best solution, but it worked for me.

How to diable captcha field using hook_form_alter(). I've tried both access and disable but no one is worked for me. I can only hide captcha field from the form. When i submit the form, it displays error message "The answer you entered for the CAPTCHA was not correct.".
This is my code at hook_form_alter():

        $form['captcha']['#access'] = FALSE;
        $form['captcha']['#disabled'] = TRUE;