How can you add the ID to the content type fields?

Question

All I see are classes, and from my understanding seems that there is nothing in the variables.

Answer 1

By default template_preprocess_field doesn't initialize the attributes array, so you don't see it when viewing the variables with the Devel module. You can achieve this and any other attributes by adding it in a template_preprocess_field() from your themes template.php file. When added it will get output to the field in template_process_field(). Here's a generic example of adding an attribute to a field. Swap all caps items for your use case...

/**
 * Implements hook_preprocess_field().
 */
function THEMENAME_preprocess_field(&$variables) {
  $content_type = $variables['element']['#bundle'];
  $view_mode = $variables['element']['#view_mode'];
  $field_name = $variables['element']['#field_name'];

  switch ($field_name) {
    // We make sure it only effects the correct field ...
    case 'FIELD_MACHINE_NAME':

      // ... and, assuming you want to limit the where an id is used, we only add on a certain content type's full node page.
      if ($view_mode === 'full' && $content_type === 'CONTENT_TYPE_MACHINE_NAME') {
          $variables['attributes_array']['id'] = 'my-id';
      }
      break;
  }
}