JS onMouseOver onMouseOut

<html>
<body>

<img onmouseover="bigImg(this)" onmouseout="normalImg(this)" border="0" src="smiley.gif" alt="Smiley" width="332" height="332">


<script>
function bigImg(x) {
    x.style.height = "64px";
    x.style.width = "64px";
}

function normalImg(x) {
    x.style.height = "32px";
    x.style.width = "32px";
}
</script>

</body>
</html>


<html>
<body>
<h1 id="demo" onmouseover="mouseOver()" onmouseout="mouseOut()">Mouse over me</h1>
<script>
function mouseOver() {
    document.getElementById("demo").style.color = "red";
}
function mouseOut() {
    document.getElementById("demo").style.color = "black";
}
</script>
</body>
</html>