I want to create a confirmation that's not limited to the message in JS.

I'm not sure I understand everything that I read in the docs.

so I create a module:

function ajax_saveconfirm_story_submit(&$form, &$form_state) {
  // What do I put here?
  
}

With some JS:

Drupal.Ajax.plugins.ajax_saveconfirm = function(hook, args) {
if (hook === 'message') {
alert("save success!");
}
}

Like this would work?

Thanks!