问题:

I'm working on an experiment & I found out that the "outline" CSS2 property is not implemented the same way on Webkit & Gecko

In the script below, I have a absolute position div inside another div but floating outside of it. The outline on Webkit outlines the actual parent div while on Gecko, it expands to cover the child item.

http://jsfiddle.net/KrCs4/

Am I missing anything? Is there a property that I need to overwrite on Gecko? or it should be reported as a bug?

Webkit Screenshot:

Firefox Screenshot:

EDIT:

It's confirmed to be a bug and here's a workaround: http://jsfiddle.net/7Vfee/ (You need to make sure that the parent is positioned: relative or absolute for this workaround to work.

回答1:

This inconsistent behavior of Gecko is well-known and quite adequately documented, although strangely not at MDN but at the SitePoint Reference:

Firefox up to and including version 3.5 will draw the outline outline around the content of an element that has overflowed its boundaries rather than around the element’s actual set dimensions.

This continues to affect all versions of Firefox. I don't see a viable workaround for it at the moment, other than to remove your absolutely-positioned div from its parent and place it relative to... something else.