In order to work with Cloudflare's Rocket Loader service, certain scripts need to have their script tags updated with the cf-async="false" attribute like so:

<script type="text/javascript" cf-async="false">

Specifically, I need to add this attribute to the Drupal settings script tag, that gets added inline at the top of every page.

My first thought was to do this via hook_js_alter(), like:

function custom_helper_js_alter(&$javascript) {
  $javascript['settings']['cf-async'] = 'false';

But it doesn't seem to be possible to add custom attribute tags via this function. So my question is, is there any way at all to do what I want without hacking core?

1 Answer 1


There is, but it's not pretty. The markup produced by drupal_get_js() is pretty closed off; it uses theme_html_tag(), but what it provides for variables means identifying the Drupal.settings script is a pain.

This is about as good as you'll get. In custom module:

function MYMODULE_preprocess_html_tag(&$vars) {
  if ($vars['element']['#tag'] == 'script' && strpos($vars['element']['#value'], 'jQuery.extend(Drupal.settings') === 0) {
    $vars['element']['#attributes']['cf-async'] = 'false';

As you rightly mentioned through the comments you could also attack it at the theme override level instead of the module level. In template.php:

function MYTHEME_preprocess_html_tag(&$variables) {
  if ($variables['element']['#tag'] == 'script' && strpos($variables['element']['#value'], 'jQuery.extend(Drupal.settings') === 0) {
    $variables['element']['#attributes']['cf-async'] = 'false';

If you have modules that mess with JavaScript (e.g. LabJS), the string match will be slightly different.

  • Thanks Clive for the helpful answer. I think you mean MYTHEME_html_tag(&$vars) in template.php, though, rather than MYMODULE_preprocess_html()? Commented Mar 24, 2015 at 16:43
  • 1
    I edited the original answer with the code that is working for me. Please feel free to re-edit, or update if that solution is not what you were intending. Commented Mar 24, 2015 at 16:50
  • It wasn't what I intended @Jordan, but your code is a perfectly valid alternative. I've changed the answer to include both
    – Clive
    Commented Mar 24, 2015 at 16:54
  • I changed the code again... I think this should be _preprocess_html_tag() in both cases (module and theme)... tested both and working as expected. hook_preprocess_html() gives different $vars that does not work with this code. Commented Mar 24, 2015 at 17:04
  • By using above approach this add attribute cf-async after the src but to make it working we need to add before src as per documentation support.cloudflare.com/hc/en-us/articles/… (point number 2 ) Please suggest how we can add it before src ?
    – jas
    Commented Nov 25, 2016 at 12:47

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