W3C home > Mailing lists > Public > www-style@w3.org > December 2009

Re: breaking overflow

From: Tab Atkins Jr. <jackalmage@gmail.com>
Date: Wed, 30 Dec 2009 11:05:00 -0600
Message-ID: <dd0fbad0912300905g380c9cf2r8f41a5731a50b018@mail.gmail.com>
To: Niels Matthijs <niels.matthijs@internetarchitects.be>
Cc: www-style <www-style@w3.org>
On Wed, Dec 30, 2009 at 2:14 AM, Niels Matthijs
<niels.matthijs@internetarchitects.be> wrote:
> I was just wondering about the overflow property the other day. In many
> cases it is used to fix certain “unwanted” behaviour. >From what I know, it
> has a nice effect on breaking collapsing margins and clearing floats.

Yup, though this isn't related to the overflow-ness per se; it's a
result of the fact that a non-auto value for overflow makes the block
into a BFC.

> In an
> older discussion it was also suggested as a fix for nested elements with
> backgrounds defined spilling over rounded corners set on parent elements.

This is related directly to overflowness.  I forget, though - is the
current behavior (child elements without rounded corners spilling out
beyond the parent element's rounded corner) intended?  Or is it
supposed to be changed, like how rounded corners are supposed to
prevent text from spilling past the corner?

> So I was wondering whether we are trying to avoid using overflow:hidden for
> unrelated effects (more control over clearing and collapsing margins) or
> whether it would be good to have a break-overflow property, allowing a
> certain element to break out any overflow:hidden set on its parent?

That's interesting, and potentially useful.  Even when I've used
overflow:hidden for correct reasons - I really do want the overflow to
be hidden - I sometimes have children that I *do* want to 'overflow'.
Often these children are abspos and just positioned outside of the

Given that I use overflow:hidden for much more than this (float
management, mostly), this might also be useful for getting around
problems with that.  There has been discussion about a property that
would create BFCs directly, though, which would allow me to stop using
overflow to hack this.  Anyone know if there is any intention of this
making it into a draft soon?

Received on Wednesday, 30 December 2009 17:05:31 UTC

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