Chile,
<!DOCTYPE html>
<html>
<head>
<title>Untitled</title>
<meta charset="utf-8">
<style type="text/css">
body *,
body.visible .preloader {
visibility: hidden;
}
body.visible *,
body .preloader {
visibility: visible;
}
</style>
</head>
<body>
<div class="preloader"></div>
<script>
window.addEventListener('load', () => {
document.body.classList.add('visible')
})
</script>
</body>
</html>