Is there a way to provide a Select All / Check All checkbox for a field that displays multiple checkboxes in Drupal 7? Seems like there is no core config to setup a "Check All" checkbox unless I missed where it is. I'm creating a content type and have a taxonomy reference field and I have alot of terms, which means alot of boxes I have to check. Anyway to provide a checkbox to select everything?
You can do a form alter. hook_form_alter and attach your js to the form.

$form['#attached']['js'] = array(
  drupal_get_path('module', 'YOURMODULE') . '/YOURMODULE.js',
);


Then add the code as in here