"Selected" Button Animation/Style

I was curious about how I could make a normal button, with a "selected" style or animation.
<button> I'm a button </button>

When you use Radiobuttons, you can see clearly that you have a selected style whenever you click on the button.
<input type="radio">

Now is the question, is it possible to have a selected style or animation (Not a click/hover animation) for the last button that you clicked (Without obviously having to use radiobuttons/checkbox).

If so, how does one make this?

JSFiddle if you want to use the code that I used in the GIF

I haven’t found a lot of articles about this, or maybe just haven’t looked good enough, anyways, maybe you people know how to do this?

>Solution :

Just toggle a class with an onclick event:

btnState = false;
btn.addEventListener("click", () => {
  btn.classList.toggle("selected");
  btnState = !btnState;
});

In the CSS add:

.selected {
  background-color: red;
}

And add an id="btn" to the button in the HTML.