disable date field (only update with datepicker) 禁用 date field 只能通过 datepicker 弹出 有大用

ie:

$form['myform']['from_date'] = array(
'#type' => 'textfield',     
'#title' => t('From date'),       
'#size' => 8,
'#default_value' => (arg(5) == null)? '0':arg(5),  
'#attributes' => array('onclick' => 'GetdatePicker(this);', 'readonly' => 'readonly'),
);

来自 http://drupal.stackexchange.com/questions/48056/disable-date-field-only-update-with-datepicker