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Re: [css3-transitions] transitioning to/from auto value

From: Tab Atkins Jr. <jackalmage@gmail.com>
Date: Tue, 27 Apr 2010 15:35:49 -0700
Message-ID: <q2ndd0fbad1004271535hb1e8b53axce2a807809dced85@mail.gmail.com>
To: Simon Fraser <smfr@me.com>
Cc: Brad Kemper <brad.kemper@gmail.com>, www-style list <www-style@w3.org>
On Tue, Apr 27, 2010 at 1:36 PM, Simon Fraser <smfr@me.com> wrote:
> I'm very reluctant to put something in a specification for which a correct implementation would be extremely difficult, and for which a "reasonable" implementation would show glitches in many common situations. I know that if we ended up implementing your suggestion in WebKit, it would not be long before we get a bug about transitioning to an 'auto' value using the wrong target size.

While I understand your reluctance, the lack of such a facility means
that it's impossible to transition the height of a <details> element
when you open/close it, frex.  I know that we authors will *strongly*
want to do so.

Actually, we'll probably be transitioning a wrapper for the contents
of the <details> instead - that is, we'll be doing this:

details > div {
  height: 0;
  overflow: hidden;
  box-sizing: border-box;
  transition: height .5s;
details[open] > div {
  height: auto;

It would be both strange and annoying if we could transition
everything else in CSS, but doing this simple native HTML widget
required either UA magic or javascript.

Received on Tuesday, 27 April 2010 22:36:47 UTC

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