Detecting classname of SVGAnimatedString

I had a problem with a SVG map I was building, the functions triggered by
onmouseover on g were not working. I used then

window.onmouseover=function(e) {
            console.log(e.target.className);
        };

to see if there was any problem with the classname, and then discovered than instead of the classname I was using, the system was detecting

SVGAnimatedString {animVal: "", baseVal: ""}

Something that never happened to me before the hundreds of times I’ve used similar code.
Any idea how can I get the actual classname of the g elements on mouseover? Thanks