background-attachment: fixed;

Desired result: the background image does not scroll at all; the test div forms a 'window' through which you look at a part of the background image. In order to see this effect properly it's best to use the window scrollbars to scroll slowly.

div.test {
	background-attachment: fixed;
}
This is the test DIV
This is the test DIV
This is the test DIV
This is the test DIV
This is the test DIV
This is the test DIV
This is the test DIV
This is the test DIV
This is the test DIV
This is the test DIV
This is the test DIV
This is the test DIV
This is the test DIV
This is the test DIV
This is the test DIV
This is the test DIV
This is the test DIV