border-image-outset

The border-image-outset CSS property sets the distance by which an element's border image is set out from its border box.

Portions of the border image that are rendered outside the border box as a result of this property do not trigger scrolling. Moreover, these areas don't capture mouse events.

Syntax

/* <length> value */
border-image-outset: 1rem;

/* <number> value */
border-image-outset: 1.5;

/* vertical | horizontal */
border-image-outset: 1 1.2;

/* top | horizontal | bottom */
border-image-outset: 30px 2 45px;

/* top | right | bottom | left */
border-image-outset: 7px 12px 14px 5px;

/* Global values */
border-image-outset: inherit;
border-image-outset: initial;
border-image-outset: unset;

The border-image-outset property may be specified as one, two, three, or four values. Each value is a <length> or <number>. Negative values are invalid.

• When one value is specified, it applies the same outset to all four sides.
• When two values are specified, the first outset applies to the top and bottom, the second to the left and right.
• When three values are specified, the first outset applies to the top, the second to the left and right, the third to the bottom.
• When four values are specified, the outsets apply to the top, right, bottom, and left in that order (clockwise).

Values

<length>

The size of the border outset as a dimension.

<number>

The size of the border outset as a multiple of the corresponding border-width.

Formal syntax

[ <length> | <number> ]{1,4}

Example

HTML

<div id="outset">This element has an outset border image!</div>

CSS

#outset {
  width: 10rem;
  background: #cef;
  border: 1.4rem solid;
  border-image: radial-gradient(#ff2, #55f) 40;
  border-image-outset: 1.5;  /* = 1.5 * 1.4rem = 2.1rem */
  margin: 2.1rem;
}

Result

Specifications

Browser compatibilityUpdate compatibility data on GitHub