====== Drupal常用API ======

===== drupal_set_html_head/drupal_add_html_head =====
Add output to the head tag of the HTML page. In Drupal7, it become drupal_add_html_head
  * http://api.drupal.org/api/function/drupal_set_html_head
  * http://api.drupal.org/api/function/drupal_add_html_head/7