z-index of an element without a closed position

Question

It is possible to know the z-index of an empty element using javascript?

For example in this code:

CSS

#exemplo1 {
    z-index:4;
}
#exemplo2 {
    z-index:4;
    position: relative;
}

HTML

<div id="exemplo1"></div>
<div id="exemplo2"></div>

It is possible to obtain the z-index of exemplo1, in this case 4, although the position is not closed?

What I have tested:

var e1 = document.getElementById('exemplo1');
var e2 = document.getElementById('exemplo2');
console.log(e1.style.zIndex); // nada
console.log(e2.style.zIndex); // nada
console.log(window.getComputedStyle(e1).getPropertyValue("z-index")); // auto no Chrome, 4 no IE11 e FF
console.log(window.getComputedStyle(e2).getPropertyValue("z-index")); // 4

jsFiddle

Answer 1

My only suggestion is to momentarily change the position of your element to relative, observe the z-index, and then back to the way it was before:

var pos = e1.style.position;
e1.style.position = "relative";
console.log(window.getComputedStyle(e1).getPropertyValue("z-index"));
e1.style.position = pos;

Example. How the Javascript execution on the main page is synchronous, This won’t cause any visual Glitch.