Detect that the browser is loading a new page to emphasize that something is happening

While UX-testing my various websites, I've often noticed that people have trouble identifying whether their "clicks" are actually doing anything.

There are multiple UI ways to handle this, like animating buttons to show they have been pushed, but I'd like to explore an alternative option.

I would like to animate my page with a loader when the browser begins to load a new page.

Is this "loading new page" status available in JS ? Can we use it for this sort of thing ? Are there any libraries built for this ?