CSS z-index Property

Definition and Usage

The z-index property specifies the stack order of an element.

An element with greater stack order is always in front of an element with a lower stack order.


Note: z-index only works on positioned elements (position:absolute, position:relative, or position:fixed).

Default value:	auto
Inherited:	no
Version:	CSS2
JavaScript syntax:	object.style.zIndex="1"

Example
Set the z-index for an image:

1. img {
2.      position:absolute;
3.      left:0px;
4.      top:0px;
5.      z-index:-1; 
6. }