作者：老葛，北京亚艾元软件有限责任公司，http://www.yaiyuan.com
接下来，我们将modules\system下面的page.tpl.php文件，复制到sites\all\themes\snt\templates文件夹下面。我建议每个学习Drupal的用户，都把这个默认模板文件看上几遍。
<?php
/**
* @file
* Default theme implementation to display a single Drupal page.
*
* The doctype, html, head and body tags are not in this template. Instead they
* can be found in the html.tpl.php template in this directory.
*
* Available variables:
*
* General utility variables:
* - $base_path: The base URL path of the Drupal installation. At the very
* least, this will always default to /.
* - $directory: The directory the template is located in, e.g. modules/system
* or themes/bartik.
* - $is_front: TRUE if the current page is the front page.
* - $logged_in: TRUE if the user is registered and signed in.
* - $is_admin: TRUE if the user has permission to access administration pages.
*
* Site identity:
* - $front_page: The URL of the front page. Use this instead of $base_path,
* when linking to the front page. This includes the language domain or
* prefix.
* - $logo: The path to the logo image, as defined in theme configuration.
* - $site_name: The name of the site, empty when display has been disabled
* in theme settings.
* - $site_slogan: The slogan of the site, empty when display has been disabled
* in theme settings.
*
* Navigation:
* - $main_menu (array): An array containing the Main menu links for the
* site, if they have been configured.
* - $secondary_menu (array): An array containing the Secondary menu links for
* the site, if they have been configured.
* - $breadcrumb: The breadcrumb trail for the current page.
*
* Page content (in order of occurrence in the default page.tpl.php):
* - $title_prefix (array): An array containing additional output populated by
* modules, intended to be displayed in front of the main title tag that
* appears in the template.
* - $title: The page title, for use in the actual HTML content.
* - $title_suffix (array): An array containing additional output populated by
* modules, intended to be displayed after the main title tag that appears in
* the template.
* - $messages: HTML for status and error messages. Should be displayed
* prominently.
* - $tabs (array): Tabs linking to any sub-pages beneath the current page
* (e.g., the view and edit tabs when displaying a node).
* - $action_links (array): Actions local to the page, such as 'Add menu' on the
* menu administration interface.
* - $feed_icons: A string of all feed icons for the current page.
* - $node: The node object, if there is an automatically-loaded node
* associated with the page, and the node ID is the second argument
* in the page's path (e.g. node/12345 and node/12345/revisions, but not
* comment/reply/12345).
*
* Regions:
* - $page['help']: Dynamic help text, mostly for admin pages.
* - $page['highlighted']: Items for the highlighted content region.
* - $page['content']: The main content of the current page.
* - $page['sidebar_first']: Items for the first sidebar.
* - $page['sidebar_second']: Items for the second sidebar.
* - $page['header']: Items for the header region.
* - $page['footer']: Items for the footer region.
*
* @see template_preprocess()
* @see template_preprocess_page()
* @see template_process()
* @see html.tpl.php
*
* @ingroup themeable
*/
?>
<div id="page-wrapper"><div id="page">
<div id="header"><div class="section clearfix">
<?php if ($logo): ?>
<a href="<?php print $front_page; ?>" title="<?php print t('Home'); ?>" rel="home" id="logo">
<img src="<?php print $logo; ?>" alt="<?php print t('Home'); ?>" />
</a>
<?php endif; ?>
<?php if ($site_name || $site_slogan): ?>
<div id="name-and-slogan">
<?php if ($site_name): ?>
<?php if ($title): ?>
<div id="site-name"><strong>
<a href="<?php print $front_page; ?>" title="<?php print t('Home'); ?>" rel="home"><span><?php print $site_name; ?></span></a>
</strong></div>
<?php else: /* Use h1 when the content title is empty */ ?>
<h1 id="site-name">
<a href="<?php print $front_page; ?>" title="<?php print t('Home'); ?>" rel="home"><span><?php print $site_name; ?></span></a>
</h1>
<?php endif; ?>
<?php endif; ?>
<?php if ($site_slogan): ?>
<div id="site-slogan"><?php print $site_slogan; ?></div>
<?php endif; ?>
</div> <!-- /#name-and-slogan -->
<?php endif; ?>
<?php print render($page['header']); ?>
</div></div> <!-- /.section, /#header -->
<?php if ($main_menu || $secondary_menu): ?>
<div id="navigation"><div class="section">
<?php print theme('links__system_main_menu', array('links' => $main_menu, 'attributes' => array('id' => 'main-menu', 'class' => array('links', 'inline', 'clearfix')), 'heading' => t('Main menu'))); ?>
<?php print theme('links__system_secondary_menu', array('links' => $secondary_menu, 'attributes' => array('id' => 'secondary-menu', 'class' => array('links', 'inline', 'clearfix')), 'heading' => t('Secondary menu'))); ?>
</div></div> <!-- /.section, /#navigation -->
<?php endif; ?>
<?php if ($breadcrumb): ?>
<div id="breadcrumb"><?php print $breadcrumb; ?></div>
<?php endif; ?>
<?php print $messages; ?>
<div id="main-wrapper"><div id="main" class="clearfix">
<div id="content" class="column"><div class="section">
<?php if ($page['highlighted']): ?><div id="highlighted"><?php print render($page['highlighted']); ?></div><?php endif; ?>
<a id="main-content"></a>
<?php print render($title_prefix); ?>
<?php if ($title): ?><h1 class="title" id="page-title"><?php print $title; ?></h1><?php endif; ?>
<?php print render($title_suffix); ?>
<?php if ($tabs): ?><div class="tabs"><?php print render($tabs); ?></div><?php endif; ?>
<?php print render($page['help']); ?>
<?php if ($action_links): ?><ul class="action-links"><?php print render($action_links); ?></ul><?php endif; ?>
<?php print render($page['content']); ?>
<?php print $feed_icons; ?>
</div></div> <!-- /.section, /#content -->
<?php if ($page['sidebar_first']): ?>
<div id="sidebar-first" class="column sidebar"><div class="section">
<?php print render($page['sidebar_first']); ?>
</div></div> <!-- /.section, /#sidebar-first -->
<?php endif; ?>
<?php if ($page['sidebar_second']): ?>
<div id="sidebar-second" class="column sidebar"><div class="section">
<?php print render($page['sidebar_second']); ?>
</div></div> <!-- /.section, /#sidebar-second -->
<?php endif; ?>
</div></div> <!-- /#main, /#main-wrapper -->
<div id="footer"><div class="section">
<?php print render($page['footer']); ?>
</div></div> <!-- /.section, /#footer -->
</div></div> <!-- /#page, /#page-wrapper -->
这仍然是HTML里面嵌套了对应的变量，这里面的变量很多，但是实际上，最常用的是区域变量，它们的调用方式都是一样的：
<?php print render($page['footer']); ?>
像page.tpl.php里面特有的变量，比如$logo、$breadcrumb，以及主导航链接，二级导航链接的输出，正在被区块的形式所取代。统一采用区块的形式，学习起来更易于掌握。
