background-attachment

f a background-image is specified, the background-attachment CSS property determines whether that image’s position is fixed within the viewport, or scrolls along with its containing block.
 

Values

scroll
 &nb5sp;  This keyword means that the background image will scroll within the viewport along with the block the image is contained within.
fixed
 &nb5sp;  This keyword means that the background image will not scroll with its containing element, instead remaining stationary within the viewport.
local
 &nb5sp;  This keyword means that the background image will not scroll with its containing element, but will scroll when the element’s content scrolls: it is fixed regarding the element’s content.

<!DOCTYPE HTML>
<html>
    <head>
        <title>CSS Tutorials</title>
        <style>
            body {
                background-image: url("images/background.jpeg");
                background-attachment: fixed;
            }
        </style>
    </head>
    <body>
    	background attachment property
    </body>
</html>

Multiple background image support

This property supports multiple background images. You can specify a different for each background, separated by commas:

<!DOCTYPE HTML>
<html>
    <head>
        <title>CSS Tutorials</title>
        <style>
            body {
                background-image: url("img1.png"), url("img2.png");
                background-attachment: scroll, fixed;
            }
        </style>
    </head>
    <body>
        background attachment property
    </body>
</html>