drupal: Form API, dynamically hide or show fields based on input
You can use the #states property to achieve that. The #states property can be applied to all Form API elements.
Here's the documentation link with an example.
simple usage example of #states: To show a select field with name 'item' only if another field with name 'type' has value 'sell'
$form['item'] = array( '#title' => t('Task Item'), '#type' => 'select', '#states' => array( // Only show this field when the value of type is sell. 'visible' => array( ':input[name="type"]' => array('value' => 'sell'), ), ), );
You could also use 'Conditional Fields' module.Here is the link: https://drupal.org/project/conditional_fieldsIt provides a 'Manage Dependencies' tab while creating a content type where you can select which fields to be visible when a field has a particular value.