populate checkbox value in text area

Question

I am a drupal newbie and am having the following problem:

In my custom content type page, I have multiple check boxes and a text area, among other fields. What I want is that, I would like the values of the checked check-boxes to be pasted inside the text area. The checkboxes are created as a multi-value field (field type = list, widget = check-box). Basically what I want is, every time the user checks/unchecks one of the checkboxes, the text area should re-populate with values of all the checkboxes that are currently selected.

I tried using the dependency fields module, but it did not solve my problem. Have anyone encountered this need before?

Based on what I read, it seems this might be possible using hook_node_presave, however I am not sure where to add this. I am using a template called norma, so I edited its template.php and added a function like so:

function norma_node_presave($node)
{ 
 print_r($node);
 exit;
}

However, nothing has happened... :(

Any pointers on how to solve this is very much appreciated...

Answer 1

hook_node_presave($node) should be included in a custom module and not in your theme !

Look at Creating Drupal 7.x modules if you want to try so.

In your hook do something like that :

function norma_node_presave($node){ 

  $value = array();
  foreach( $node->field_checkbox['und'] as $checkbox){
    $value[] = $checkbox['value'];
  }

  $node->field_textfield['und'][0]['value'] = implode('<br>', $value);
}

Answer 2

The best idea would be to use Javascript (so that as you check the checkbox the field value changes), you can do something like this.

$(document).ready(function() {
    $('#checkbox1').change(function() {
        $('.field1').val($(this).val());  
    });
});

Or something like that, I can't guarantee that code works but it should get you started.