A way to have an unchecked "end date" input field? The date module gives the possiblity to collect an end date.
The thing is, in the node creation form, 'Show end date' is checked by default and the date calendar popup field is displayed.
  

I would like to have the opposite scenario.
With the End date field hidden by default, and it would only appear if we check the 'Show end date' checkbox.


Thanks to anyone who can help with this
We can do this easily using hook_form_alter hook, by setting #checked value of checkbox to FALSE. Since the date module doesn't add both fields at initial form load, we've to add #after_build to form where we can modify #checked value of checkbox (i.e. show_todate field) in form.

Below is the sample code for hiding the end date in date field. For this we've to add a Date Type field (field name as field_date) with ability to add end date in article Content Type. After which we've to implement hook_form_alter and checked if current form is add new article form to make sure we don't override node edit field value. And then added #after_build to add article form. Which then set the #checked value to FALSE.

/**
 * Implements hook_form_alter().
 */
function [MODULE_NAME]_form_alter(&amp;$form, &amp;$form_state, $form_id) {
  switch ($form_id) {
    case 'article_node_form':
      if (empty($form['nid']['#value'])) {
        $form['#after_build'][] = '_modify_end_date_form';
      }
      break;
  }
}

/**
 * Proxy function to call _modify_end_date_form_after_build().
 * @param type $form
 * @param type $form_state
 * @return void
 */
function _modify_end_date_form($form, &amp;$form_state) {
  return _modify_end_date_form_after_build($form, $form_state);
}

/**
 * After_build callback for Article Content Type.
 * @param type $form
 * @param type $form_state
 * @return void
 */
function _modify_end_date_form_after_build($form, &amp;$form_state) {
  $form['field_date'][LANGUAGE_NONE][0]['show_todate']['#checked'] = FALSE;
  // $form['field_date'][LANGUAGE_NONE][0]['show_todate']['#value'] = FALSE;
  return $form;
}