<!DOCTYPE html>
<html>
<body style="background:#f3f3f3 url('w3css.gif') no-repeat fixed;">
<h1>Hello World!</h1>
<p>The background-image is fixed.</p>
<p>The background-image is fixed.</p>
<p>The background-image is fixed.</p>
<p>The background-image is fixed.</p>
<p>The background-image is fixed.</p>
<p>The background-image is fixed.</p>
<button onclick="myFunction()">Get background-attachment value</button>
<script>
function myFunction() {
alert(document.body.style.backgroundAttachment);
}
</script>
</body>
</html>