plain javascript code to highlight an html element

Question

to debug some javascript code, I am looking for javascript code (preferably just js, without libraries and dependencies) that can highlight a div or span (probably by putting over it a div or span of the same size and shape with a bright color and some transparency).

I pretty sure it can be done, but I don't know how to start.

CLARIFICATION

I need to put a semi transparent div on top of my element. Modifying the background or adding borders will not help as my elements have themselves backgrounds and borders.

Answer 1

---

If for some reason you need to use javascript here is function that temporary highlits element background

function highlight(element) {
    let defaultBG = element.style.backgroundColor;
    let defaultTransition = element.style.transition;

    element.style.transition = "background 1s";
    element.style.backgroundColor = "#FDFF47";

    setTimeout(function()
    {
        element.style.backgroundColor = defaultBG;
        setTimeout(function() {
            element.style.transition = defaultTransition;
        }, 1000);
    }, 1000);
}