How do I add an active class to the current element?

Learn how to add an active class to the current element with JavaScript.

You can read on how to do it in this tutorial: https://www.w3schools.com/howto/howto_js_active_element.asp

Highlight the active/current (pressed) button:

Try it yourself here: https://www.w3schools.com/howto/tryit.asp?filename=tryhow_js_active_element