<!DOCTYPE html>
<html>
<body>

<p>This example uses the addEventListener() method to attach a "mouseenter" and "mouseleave" event to a h1 element.</p>

<h1 id="demo">Mouse over me</h1>

<script>
document.getElementById("demo").addEventListener("mouseenter", mouseEnter);
document.getElementById("demo").addEventListener("mouseleave", mouseLeave);

function mouseEnter() {
    document.getElementById("demo").style.color = "red";
}

function mouseLeave() {
    document.getElementById("demo").style.color = "black";
}
</script>

</body>
</html>