My customer would like to publish animations on an institutional websites which works : with a Jalios CMS and a Drupal CMS
The security is very high and only allows text input (no CSS possible for example).
The user can only enter text.
It sounds like it would be better for your customer to upload their content to a different server and embed it on a page in the more restrictive environment. They could use Tiiny Host which makes uploading the content very simple. Here's a webinar that we did with Tiiny Host with more information.
I double-checked with Justin. He said that, no, you couldn't strip all of the CSS and JS to put on an external server.
He said that you could probably move the CSS and JS to another server, but you'd have to make some manual updates to the files as they include relative links to the content.