Outline

Not supported by Explorer Windows and iCab.

Buggy in Safari. The bug is solved in 3.0 Windows, but I've heard that it still exists on the Mac version.

The outline of a box is almost the same as the border. Unfortunately the four browsers that support it use three radically different definitions of outline.

The outline is not actually a part of the box, it does not count in any way towards the width or height of a box.

Its syntax is the same as for the border: width, style and color. Unlike a border, adding special instructions for one side of the outline (like outline-left-width) is not possible. You can define only a complete outline around the entire element.

Example

p.test {
	outline: 3px solid #6374AB;
	border: 1px solid #000000;
	width: 20em;
}

<p class="test">

The results

The Safari result shown here is for older versions.

Results of my outline test; Standard vs. Safari

Browsers used to be wildly incompatible in their outline support, but fortunately their support has stabilized to the "Standard" version in the screenshot.