Sometimes, you will need to include JavaScript code in the admin interface. A common requirement is to use an HTML editor, such as CKEditor, for your TextField.
There are several ways to implement this in Django, for example, using a Media inner class on your ModelAdmin class. However, I find extending the admin change_form template to be the most convenient approach.
For example, if you have an app called posts, then you will need to create a file called change_form.html within the templates/admin/posts/ directory. If you need to show CKEditor (it could be any JavaScript editor, but this one is the one I prefer) for the message field of a model in this app, then the contents of the file can be ...