drupal_add_css

Definition

drupal_add_css($path = NULL, $type = 'module', $media = 'all', $preprocess = TRUE)
includes/common.inc, line 1434

Description

Adds a CSS file to the stylesheet queue.

What does this actually mean? CSS preprocessing is the process of aggregating a bunch of separate CSS files into one file that is then compressed by removing all extraneous white space.

The reason for merging the CSS files is outlined quite thoroughly here: http://www.die.net/musings/page_load_time/ "Load fewer external objects. Due to request overhead, one bigger file just loads faster than two smaller ones half its size."

However, you should *not* preprocess every file as this can lead to redundant caches. You should set $preprocess = FALSE when:

Your styles are only used rarely on the site. This could be a special admin page, the homepage, or a handful of pages that does not represent the majority of the pages on your site.

Typical candidates for caching are for example styles for nodes across the site, or used in the theme.

Parameters

$path (optional) The path to the CSS file relative to the base_path(), e.g., /modules/devel/devel.css.

$type (optional) The type of stylesheet that is being added. Types are: module or theme.

$media (optional) The media type for the stylesheet, e.g., all, print, screen.

$preprocess (optional) Should this CSS file be aggregated and compressed if this feature has been turned on under the performance section?

Return value

An array of CSS files.

Name	Description
Input validation	Functions to validate user input.

Code

<?php
function drupal_add_css($path = NULL, $type = 'module', $media = 'all', $preprocess = TRUE) {
  static $css = array();

  // Create an array of CSS files for each media type first, since each type needs to be served
  // to the browser differently.
  if (isset($path)) {
    // This check is necessary to ensure proper cascading of styles and is faster than an asort().
    if (!isset($css[$media])) {
      $css[$media] = array('module' => array(), 'theme' => array());
    }
    $css[$media][$type][$path] = $preprocess;
  }

  return $css;
}
?>