box-pack CSS property

Non-standard: This feature is not standardized. We do not recommend using non-standard features in production, as they have limited browser support, and may change or be removed. However, they can be a suitable alternative in specific cases where no standard option exists.

Deprecated: This feature is no longer recommended. Though some browsers might still support it, it may have already been removed from the relevant web standards, may be in the process of being dropped, or may only be kept for compatibility purposes. Avoid using it, and update existing code if possible; see the compatibility table at the bottom of this page to guide your decision. Be aware that this feature may cease to work at any time.

Warning: This is a property of the original CSS flexible box layout Module draft, and has been replaced by a newer standard. See flexbox for information about the current standard.

The -moz-box-pack and -webkit-box-pack CSS properties specify how a -moz-box or -webkit-box packs its contents in the direction of its layout. The effect of this is only visible if there is extra space in the box.

The direction of layout depends on the element's orientation: horizontal or vertical.

Syntax

css
/* Keyword values */
box-pack: start;
box-pack: center;
box-pack: end;
box-pack: justify;

/* Global values */
box-pack: inherit;
box-pack: initial;
box-pack: unset;

The box-pack property is specified as one of the keyword values listed below.

Values

start

The box packs contents at the start, leaving any extra space at the end.

center

The box packs contents in the center, dividing any extra space equally between the start and the end.

end

The box packs contents at the end, leaving any extra space at the start.

justify

The space is divided evenly in-between each child, with none of the extra space placed before the first child or after the last child. If there is only one child, treat the value as if it were start.

Notes

The edge of the box designated the start for packing purposes depends on the box's orientation and direction:

  • For horizontal elements, the start is the top edge.
  • For vertical elements, the start is the left edge.
Normal Reverse
Horizontal left right
Vertical top bottom

The edge opposite to the start is designated the end.

If the packing is set using the element's pack attribute, then the style is ignored.

Formal definition

Initial valuestart
Applies toelements with a CSS display value of -moz-box, -moz-inline-box, -webkit-box or -webkit-inline-box
Inheritedno
Computed valueas specified
Animation typediscrete

Formal syntax

box-pack = 
start |
center |
end |
justify

Examples

Examples of box-pack

css
div.example {
  border-style: solid;

  display: -moz-box; /* Mozilla */
  display: -webkit-box; /* WebKit */

  /* Make this box taller than the children,
     so there is room for the box-pack */
  height: 300px;
  /* Make this box wide enough to show the contents
     are centered horizontally */
  width: 300px;

  /* Children should be oriented vertically */
  -moz-box-orient: vertical; /* Mozilla */
  -webkit-box-orient: vertical; /* WebKit */

  /* Align children to the horizontal center of this box */
  -moz-box-align: center; /* Mozilla */
  -webkit-box-align: center; /* WebKit */

  /* Pack children to the bottom of this box */
  -moz-box-pack: end; /* Mozilla */
  -webkit-box-pack: end; /* WebKit */
}

div.example p {
  /* Make children narrower than their parent,
     so there is room for the box-align */
  width: 200px;
}
html
<div class="example">
  <p>I will be second from the bottom of div.example, centered horizontally.</p>
  <p>I will be on the bottom of div.example, centered horizontally.</p>
</div>

Specifications

Not part of any standard.

Browser compatibility

desktop mobile
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
box-pack
Deprecated Non-standard
Chrome – Full support
Chrome 1 (Release date: 2008-12-11)
prefix
prefix Implemented with the vendor prefix: -webkit-
Edge – Full support
Edge 12 (Release date: 2015-07-29)
prefix
prefix Implemented with the vendor prefix: -webkit-
Firefox – Full support
Firefox 1 (Release date: 2004-11-09)
prefix
prefix Implemented with the vendor prefix: -moz-
Firefox – Full support
Firefox 49 (Release date: 2016-09-20)
prefix
prefix Implemented with the vendor prefix: -webkit-
Opera – Full support
Opera 15 (Release date: 2013-07-02)
prefix
prefix Implemented with the vendor prefix: -webkit-
Safari – No support
Safari 1.1 – 2 (Release date: 2003-10-24)
prefix
prefix Implemented with the vendor prefix: -khtml-
Safari – Full support
Safari 3 (Release date: 2007-10-26)
prefix
prefix Implemented with the vendor prefix: -webkit-
Chrome Android – Full support
Chrome Android 18 (Release date: 2012-06-27)
prefix
prefix Implemented with the vendor prefix: -webkit-
Firefox for Android – Full support
Firefox for Android 4 (Release date: 2011-03-29)
prefix
prefix Implemented with the vendor prefix: -moz-
Firefox for Android – Full support
Firefox for Android 49 (Release date: 2016-09-20)
prefix
prefix Implemented with the vendor prefix: -webkit-
Opera Android – Full support
Opera Android 14 (Release date: 2013-05-21)
prefix
prefix Implemented with the vendor prefix: -webkit-
Safari on iOS – Full support
Safari on iOS 1 (Release date: 2007-06-29)
prefix
prefix Implemented with the vendor prefix: -webkit-
Samsung Internet – Full support
Samsung Internet 1 (Release date: 2013-04-27)
prefix
prefix Implemented with the vendor prefix: -webkit-
WebView Android – Full support
WebView Android 4.4 (Release date: 2013-12-09)
prefix
prefix Implemented with the vendor prefix: -webkit-
WebView on iOS – Full support
WebView on iOS 1 (Release date: 2007-06-29)
prefix
prefix Implemented with the vendor prefix: -webkit-

Legend

Tip: you can click/tap on a cell for more information.

Full support
Full support
Non-standard. Check cross-browser support before using.
Deprecated. Not for use in new websites.
Requires a vendor prefix or different name for use.
Has more compatibility info.

See also