JSFiddle - React, Tailwind, and code Playground

HTML

<div id="mydiv">sjdfajkbhjcxcx</div>

JavaScript

window.onmouseover = function (e) {
    mouseOver(e)
};
document.getElementById("mydiv").onmouseout = function (e) {
    mouseOut(e)
};

function mouseOver(e) {
    if (e.target.nodeName === "DIV") {
        alert("it's a div");
    }
}

function mouseOut() {
    document.getElementById("mydiv").style.color = "black";
}