The 
background-attachment property is used to specify whether or not the background image scrolls with the document.
The possible values are.
| Properties | Description | 
|---|
| fixed | the image is fixed relative to the view-port | 
| scroll | the image is fixed relative to the document, and the two will be scrolled together (the default value) | 
snippet
<html>
<head>
    <style>
        p {width:300px; height:250px; background-image: url(bg.jpg)}
    </style>
</head>
<body>
    <form>
        <p style="background-attachment: fixed; overflow: fixed">
		Commodi numquam adipisci sit consequatur vitae saepe beatae, vero sit dignissimos 
		harum accusamus fuga iusto facilis expedita omnis beatae, dolorum perferendis harum 
		blanditiis nemo cumque dignissimos recusandae a aliquid, laboriosam</p>
        <p style="background-attachment: fixed; overflow: scroll">
                Commodi numquam adipisci sit consequatur vitae saepe beatae, vero sit dignissimos 
		harum accusamus fuga iusto facilis expedita omnis beatae, dolorum perferendis harum 
		blanditiis nemo cumque dignissimos recusandae a aliquid, laboriosam</p>
    </form>
</body>
</html>