CSS background-attachment

<!DOCTYPE html>
<title>Example</title>
<style>
.contentBox {
	width: 300px;
	height: 200px;
	border: 1px solid #000000;
	overflow: scroll;
  background-image: url("/pix/samples/bg1.gif");
	background-repeat: no-repeat;
	background-attachment: fixed;
}
</style>
<div class="contentBox">
  <p>As the W3C says:</p>
    <blockquote>
      <p>If a background image is specified, this property specifies whether it is fixed with regard to the viewport ('fixed') or scrolls along with the containing block ('scroll').</p>

      <p>Note that there is only one viewport per view. If an element has a scrolling mechanism (see 'overflow'), a 'fixed' background doesn't move with the element, and a 'scroll' background doesn't move with the scrolling mechanism.</p>

      <p>Even if the image is fixed, it is still only visible when it is in the content, padding or border area of the element. Thus, unless the image is tiled ('background-repeat: repeat'), it may be invisible.</p>
    </blockquote>
</div>

The CSS background-attachment property specifies whether a background image should be fixed or scroll with the containing block.

Syntax

Where:

Possible Values

fixed: The background is fixed with regard to the viewport. In paged media where there is no viewport, the background is fixed with respect to the page box and therefore replicated on every page.
local: The background is fixed with regard to the element's contents: if the element has a scrolling mechanism, the background scrolls with the element's contents, and the background painting area and background positioning area are relative to the scrollable area of the element rather than to the border framing them.
scroll: The background is fixed with regard to the element itself and does not scroll with its contents.

In addition, all CSS properties also accept the following CSS-wide keyword values as the sole component of their property value:

initial: Represents the value specified as the property's initial value.
inherit: Represents the computed value of the property on the element's parent.
unset: This value acts as either inherit or initial, depending on whether the property is inherited or not. In other words, it sets all properties to their parent value if they are inheritable or to their initial value if not inheritable.

General Information

Initial Value: scroll
Applies To: All elements
Inherited?: No
Media: Visual

Example Code

Official Specifications

CSS Backgrounds and Borders Module Level 3 (W3C Candidate Recommendation 9 September 2014)
CSS Level 2.1 (W3C Recommendation 07 June 2011)
CSS Level 1 (W3C Recommendation 17 Dec 1996)