drupal_add_css, drupal_add_js does not work

Question

I am using drupal_add_css() and drupal_add_js() to add CSS and JavaScript files to my Drupal site. I am doing this in a module called control so th

Answer 1

The reason these functions aren't working within the preprocess_page() function is that template_preprocess_page() (which is called first) has already formatted the structured content into variables $scripts and $styles. If you want to add additional js or css at the preprocess level, you need to regenerate those 2 variables, something like this:

function control_preprocess_page(&$vars) {
  // Add new CSS.
  drupal_add_css('path/to/css/foo.css');
  // Rebuild the 'styles variable.
  $vars['styles'] = drupal_get_css();

  // Add new JS.
  drupal_add_js(...);
  $vars['scripts'] = drupal_get_js();
}

Using drupal_add_js/drupal_add_css in hook_init, or a more precisely targeted function (eg, an alter hook, or nodeapi hook, if applicable), will avoid having to regenerate those variables.