JSFiddle - React, Tailwind, and code Playground
HTML
<html>
<head>
<script>
function hide(obj) {
obj.style.opacity = obj.style.opacity*1 - 0.1;
if (obj.style.opacity > 0) setTimeout(function() {hide(obj)}, 10);
}
function show(obj) {
obj.style.opacity = obj.style.opacity*1 + 0.1;
if (obj.style.opacity <= 1) setTimeout(function() {show(obj)}, 10);
}
</script>
</head>
<body>
<img id="pict" style="opacity: 1;" src="http://www.google.com.ua/images/nav_logo99.png" alt="" onmouseover="hide(this)" onmouseout="show(this)">
</body>
</html>