Editing Z-order (section)

==z-index{{Anchor|ZX}}==
The actual number assigned to a particular place in the Z-order is sometimes known as the z-index.  In particular the [[CSS]] property that sets the stack order of specific elements is known as the z-index.  An element with greater stack order is always in front of another element with lower stack order.<ref name="W3C-zindex"/>

<syntaxhighlight lang="css">
p {
  position: relative;
  z-index: -1;
}
</syntaxhighlight>

Negative stack orders can also be used in the same manner. A negative value will appear behind a positive one. <code>z-index</code> only works on elements that have a position value (e.g. <code>position: relative;</code>) and for many coders, this one of the first things to investigate when debugging why the z-index isn't working.<ref>{{Cite web|url=https://www.thewebdeveloperguide.com/css-z-index-not-working-send-help/|title=CSS Z-Index Not Working! Send Help!|date=2019-03-28|website=The Web Developer Guide|language=en-US|access-date=2019-04-10}}</ref>

Like all other CSS properties, it can be set with [[JavaScript]] as well with the following syntax:

<syntaxhighlight lang="javascript">
object.style.zIndex= '1';
</syntaxhighlight>