Question

I want to build a module that adds an extra field on the search form block configuration page to store text that will be displayed as the HTML5 placeholder attribute. What hooks do I need to use and how do I modify just the search form block to have that extra texbox that then gets printed on the page?

Answer 1

This is the code that finally worked, thanks for your help:

function yourmodule_form_alter(&$form, &$form_state, $form_id) {  
  if (($form_id == 'block_admin_configure') && ($form['module']['#value'] == 'search')) {
    $form['settings']['theplaceholder'] = array(
      '#type' => 'textfield', 
      '#title' => t('Add placeholder text'), 
      '#default_value' => variable_get('theplaceholder'),
      '#maxlength' => 64,
      '#description' => 'Override the default placeholder',
      '#weight' => 2,
      '#access' => TRUE,
    );
    $form['#submit'][] = 'yourmodule_submit_function';
  }

if ($form_id == 'search_block_form') {
    $form['search_block_form']['#attributes']['placeholder'] = variable_get('theplaceholder');
  }
}
function yourmodule_submit_function($delta = '', $edit = array()){  
    variable_set('theplaceholder', $edit['values']['theplaceholder']);
}