z-index

The z-index sets the stack order of an element.

Syntax

z-index: <value>;

The z-index value can be specified with a positive or negative integer. An element with a larger z-index value will be higher on the stack than an element with a lower z-index value. Unless specified, the default value of an element on the stack is 0.

Note: The z-index property does not work with an element that has a position value of static.

Example 1

In the following example, we have a gray box and a black box. We can set the gray box above the black box by giving the gray box a higher z-index value.

.graybox {
  z-index: 2;
}

.blackbox {
  z-index: 1;
}

Example 2

If we wanted to have the black box above the gray box, we can simply give the black box a higher z-index value.

.graybox {
  z-index: 2;
}

.blackbox {
  z-index: 3;
}