What are the Pre-Defined Variables that drupal provides?

Available variables

$base_path:

Returns the base URL path of the Drupal installation. At the very least, this will always default to /.

$breadcrumb:

HTML for displaying the breadcrumbs at the top of the page.

$closure:

Needs to be displayed at the bottom of the page, for any dynamic javascript that needs to be called once the page has already been displayed.

$content:

The HTML content generated by Drupal to be displayed.

$css:

An array of all the CSS files for the current page.

$directory:

The directory the theme is located in, e.g.

themes/garland or themes/garland/minelli.

$feed_icons:

A string of all feed icons for the current page.

$footer_message:

The footer message as defined in the admin settings, also the HTML for the footer region.

$head:

HTML as generated by drupal_get_html_head().

$head_title:

The text to be displayed in the page title.

$header:

HTML for the header region.

$help:

Dynamic help text, mostly for admin pages.

$is_front:

True if the front page is currently being displayed. Used to toggle the mission.

$language:

The language the site is being displayed in.

$layout:

This setting allows you to style different types of layout ('none', 'left', 'right' or 'both') differently, depending on how many sidebars are enabled.

$logo:

The path to the logo image, as defined in theme configuration.

$messages:

HTML for status and error messages, to be displayed at the top of the page.

$mission:

The text of the site mission, empty when display has been disabled in theme settings.

$node

(5.x and after only) If you are in page.tpl.php displaying a node in full page view then $node is available to your template.

$onload_attribute:

(4.7 and older only) Onload tags to be added to the head tag, to allow for autoexecution of attached scripts.

$primary_links (array)

An array containing the links as they have been defined in the phptemplate specific configuration block.

$scripts:

(5.x and after only) HTML to load the JavaScript files and make the JS settings available. Previously, javascript files are hardcoded into the page.tpl.php

$search_box:

True(1) if the search box has been enabled.

$search_button_text:

(4.7 and older only)Translated text on the search button.

$search_description:

(4.7 and older only)Translated description for the search button.

$search_url:

(4.7 and older only)URL the search form is submitted to.

$secondary_links (array):

An array containing the links as they have been defined in the phptemplate specific configuration block.

$sidebar_left:

The HTML for the left sidebar.

$sidebar_right:

The HTML for the right sidebar.

$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.

$styles:

Required for stylesheet switching to work. This prints out the style tags required.

$tabs:

HTML for displaying tabs at the top of the page.

$title:

Title, different from head_title, as this is just the node title most of the time. Enjoy Drupaling. Cheers!