border-image-width

The border-image-width CSS property sets the width of an element's border image.

If this property's value is greater than the element's border-width, the border image will extend beyond the padding (and/or content) edge.

Syntax

/* Keyword value */
border-image-width: auto;

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

/* <percentage> value */
border-image-width: 25%;

/* <number> value */
border-image-width: 3;

/* top and bottom | left and right */
border-image-width: 2em 3em;

/* top | left and right | bottom */
border-image-width: 5% 15% 10%;

/* top | right | bottom | left */
border-image-width: 5% 2em 10% auto;

/* Global values */
border-image-width: inherit;
border-image-width: initial;
border-image-width: revert;
border-image-width: revert-layer;
border-image-width: unset;

The border-image-width property may be specified using one, two, three, or four values chosen from the list of values below.

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

Values

<length-percentage>: The width of the border, specified as a <length> or a <percentage>. Percentages are relative to the width of the border image area for horizontal offsets and the height of the border image area for vertical offsets. Must not be negative.
<number>: The width of the border, specified as a multiple of the corresponding border-width. Must not be negative.
auto: The width of the border is made equal to the intrinsic width or height (whichever is applicable) of the corresponding border-image-slice. If the image does not have the required intrinsic dimension, the corresponding border-width is used instead.

Formal definition

Initial value	1
Applies to	All elements, except internal table elements when border-collapse is collapse
Inherited	no
Computed value	four values, each either a number, the keyword auto, or a computed <length-percentage> value
Animation type	by computed value

Formal syntax

[ <length-percentage [0,∞]> | <number [0,∞]> | auto ]{1,4}

Examples

Tiling a border image

This example creates a border image using the following ".png" file, which is 90 by 90 pixels:

Square image containing eight circles. The circles in each corner are light purple. The four side circles are blue. The area in the middle, where a ninth circle could fit, is blank.

Thus, each circle in the source image is 30 by 30 pixels.

HTML

<p>
  Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy
  eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam
  voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita
  kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet.
</p>

CSS

p {
  border: 20px solid;
  border-image: url("border.png") 30 round;
  border-image-width: 16px;
  padding: 40px;
}

css properties border-image-width