Drupal 7 Module Development

Chapter 10
The second argument can contain an array of options to be used including group,
scope, and preprocess. Once CSS is added, with a weight of CSS_THEME set to not
preprocess, it will look like:
$options = array(
'type' => 'inline',
'group' => CSS_THEME,
'preprocess' => FALSE,
);
drupal_add_css("body { color: #ffffff; }", $options);
API Documentation for drupal_add_css() is available at
http://api.drupal.org/api/function/drupal_add_css/7
Using the Library API
Drupal 7 provides a Library API where libraries and plugins of JavaScript and CSS
can be defined and programmatically added later. jQuery and the other libraries
provided with Drupal are all defined using the system modules implementation of
hook_library(). We can use farbtastic, a jQuery color picker included with Drupal,
as an example. Included in farbtastic is a JavaScript file and a CSS file. To add
farbtastic to a page it would look as follows:
drupal_add_library('system', 'farbtastic');
This will not only add JavaScript and CSS, but will also add any dependent libraries.
An example of this can be seen in the overlay module where drupal_add_library()
adds the overlay. A call is made to add the parent overlay JavaScript that looks
like this:
drupal_add_library('overlay', 'parent');
In the function overlay_library(), parent is set to have jQuery BBQ and jQuery
UI core as dependencies to the overlay parent. This means those two libraries
will be added to the page before the overlay. Drupal knows the library chain of
dependencies, so you don't have to.
API documentation about drupal_add_library() is available at
http://api.drupal.org/api/function/drupal_add_library/7.
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