I am trying to override Drupal.ajax.prototype.beforeSend like this:

(function($) {
  // In mymodule.js, which appears after ajax.js in the page build
  Drupal.ajax.prototype.beforeSend = function(xmlhttprequest, options) {

The file that contains the code is listed below core's ajax.js in the page's source, yet it's the console.log I put inside core's ajax.js beforeSend that is showing up.

What else is to it? Has anything been changed in Drupal? Using version 9.3. Can't override any of those functions.

  • Did you also pass in the 'Drupal' object?
    – Kevin
    May 2, 2022 at 14:15
  • I even passed 'jQuery, Drupal, drupalSettings'.
    – KrzysiekK
    May 2, 2022 at 14:17
  • 2
    Isn't ajax spelled Ajax?
    – 4uk4
    May 2, 2022 at 14:19
  • Wow, actually there are both "ajaxes", and the one I need is, indeed, spelled 'Ajax'. Thank you! Can't mark the comment as the answer though.
    – KrzysiekK
    May 2, 2022 at 14:22

1 Answer 1


There are two javascript objects:

  1. Drupal.ajax
  2. Drupal.Ajax

You have to override the prototypes in Drupal.Ajax. For each Ajax object declared in Drupal settings an instance of it will then be stored in Drupal.ajax.instances.

  • Do you know where this is documented? I looked around a little and I mostly just find answers to questions like this, with information like this, but no linked source.
    – sonfd
    May 2, 2022 at 15:10

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