negative padding

[roedygr]

padding: -10px 0px 0px 0px; /* inner t r b l */

This validates ok with HTMLValidator and with TopStyle. However it fails W3C CSS validator.

The book I learned CSS from told me it was OK.

It crashes Amaya browser.

The spec at http://www.w3.org/TR/CSS21/box.html#propdef-padding says nothing one way or the other.

What's the scoop?

[MikeGale]

Hi,

I'm not an expert on this.

It did interest me though, so I searched and found two web pages that talk about only non-negative padding being allowed.

See:

http://archivist.incutio.com/viewlist/css-discuss/42541

http://www.w3.org/TR/CSS21/box.html

The latter (which is W3C about CSS 2.1) says:

Unlike margin properties, values for padding values cannot be negative. Like margin properties, percentage values for padding properties refer to the width of the generated box's containing block.

(I know that negative margins are used by some "stylists" and are officially allowed.)

There's presumably some design discussion about this in the W3C archives. It might be worth a warning in CSE.

[roedygr]

Aha! The book I read on CSS probably told me that negative margins were ok, and I just presumed that negative paddings were ok too.

So CSEvalidator and TopStyle are improperly letting negative paddings through.

[Lou]

Code: Select all

.oddone     {position: absolute;
             top: -250px; left: -250px;
            }


The above CSS validate with http://jigsaw.w3.org/css-validator as part of a URL or direct input.

[Albert Wiersch]

Yes, padding values should not be negative. This has already been addressed/fixed in v10. I'm sorry for the trouble.

I plan to have a public BETA out for v10 sometime this month.

http://www.w3.org/TR/css3-box/#the-padding

Sets the thickness of the padding area. The value may not be negative.