CSS border-image

The border-image property is one of the properties introduced in CSS3 for the purposes of enabling images to be used on CSS borders.

The CSS border-image property is a shorthand property for setting multiple "border image" related properties in one place. This is an efficient way of adding images to your borders.

The border-image property sets the border-image-source, border-image-slice, border-image-width, border-image-outset, and border-image-repeat properties.

Note that setting an image border will override any border that has been specified using the border-style properties. However, if the image cannot be loaded, or if the border-image value is none, the border styles will be used instead.

Syntax

border-image: <'border-image-source'> || <'border-image-slice'> [ / <'border-image-width'> | / <'border-image-width'>? / <'border-image-outset'> ]? || <'border-image-repeat'>

Possible Values

<'border-image-source'>
Specifies the location of the image. For more information, see the border-image-source property.
<'border-image-slice'>
Specifies inward offsets from the top, right, bottom, and left edges of the image, dividing it into nine regions: four corners, four edges and a middle. For more information, see the border-image-slice property.
<'border-image-width'>
Specifies the width of the border image. This defines the border image area, which is the area used to draw the image. For more information, see the border-image-width property.
<'border-image-outset'>
Specifies the amount by which the border image area extends beyond the border box. For more information, see the border-image-outset property.
<'border-image-repeat'>
Specifies how the images for the middle part and sides of the border are scaled and tiled. The first keyword applies to the horizontal sides, the second to the vertical ones. If the second keyword is absent, it is assumed to be the same as the first. Values have the following meanings:
stretch
The image is stretched to fill the area.
repeat
The image is repeated (i.e. "tiled") to fill the area.
round
The image is repeated (tiled) to fill the area. If it does not fill the area with a whole number of tiles, the image is rescaled so that it does.
space
The image is repeated (tiled) to fill the area. If it does not fill the area with a whole number of tiles, the extra space is distributed around the tiles.
For more information, see the border-image-repeat property.

In addition, all CSS properties also accept the following CSS-wide keyword values as the sole component of their property value:

initial
Represents the value specified as the property's initial value.
inherit
Represents the computed value of the property on the element's parent.
unset
This value acts as either inherit or initial, depending on whether the property is inherited or not. In other words, it sets all properties to their parent value if they are inheritable or to their initial value if not inheritable.

Basic Property Information

Initial Value
See individual properties
Applies To
See individual properties
Inherited?
No
Media
Visual

Example Code

Basic CSS

border-image: url(/images/border.png) 30 30 round;

Working Example within an HTML Document

<!DOCTYPE html>
<title>Example</title>
<style>
.cool-border {
  width: 200px;
  padding: 30px;
  border: 1em double #edb742;
  border-image: url(/pix/css/css3/properties/border-image-1.png) 30 30 round;
}
</style>
<div class="cool-border">
  This box has a cool border?
</div>

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CSS Specifications

Browser Support

The following table provided by Caniuse.com shows the level of browser support for this feature.

Vendor Prefixes

For maximum browser compatibility many web developers add browser-specific properties by using extensions such as -webkit- for Safari, Google Chrome, and Opera (newer versions), -ms- for Internet Explorer, -moz- for Firefox, -o- for older versions of Opera etc. As with any CSS property, if a browser doesn't support a proprietary extension, it will simply ignore it.

This practice is not recommended by the W3C, however in many cases, the only way you can test a property is to include the CSS extension that is compatible with your browser.

The major browser manufacturers generally strive to adhere to the W3C specifications, and when they support a non-prefixed property, they typically remove the prefixed version. Also, W3C advises vendors to remove their prefixes for properties that reach Candidate Recommendation status.

Many developers use Autoprefixer, which is a postprocessor for CSS. Autoprefixer automatically adds vendor prefixes to your CSS so that you don't need to. It also removes old, unnecessary prefixes from your CSS.

You can also use Autoprefixer with preprocessors such as Less and Sass.