sitecats bundles JS providing some additional functionality.
Do not forget to include JS file in your HTML to use it:
<script src="{{ STATIC_URL }}js/sitecats/sitecats.min.js"></script>
Note
jQuery is required for sitecats client side functionality.
To convert your categories list into a cloud where category title font size depends upon a number
of items belonging to this category, use make_cloud() method.
// `article_categories` is an ID of HTML element containing categories lists.
sitecats.make_cloud('article_categories');