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

Re: PF-Wg feedback on CSS animations

From: Dean Jackson <dino@apple.com>
Date: Mon, 27 Apr 2009 18:23:33 +1000
Cc: www-style@w3.org
Message-Id: <12D2EC52-D9A0-45E9-9304-9D73FD26B5E5@apple.com>
To: Jonathan Snook <jonathan.snook@gmail.com>

On 26/04/2009, at 1:29 PM, Jonathan Snook wrote:

> On 24-Apr-09, at 4:03 PM, Dean Jackson wrote:
>> We didn't see as much need for a transitionStart event. Can you  
>> think of places where you need it because the functionality isn't  
>> available elsewhere? For example, if you are changing property  
>> values via JS you're already in a better place to set up the  
>> transition.
> While I don't have a particular use case at the moment, I could see  
> where you might have transitions defined on generic elements and  
> transitions being initiated via :hover. To determine  
> transitionStart, it'd be more cumbersome to have to do DOM traversal  
> and trap mouseover event handlers.
> For example, maybe I have a sidebar with links that have a  
> transition on them using something like:
> #sidebar a { /* define transition */ }
> #sidebar a:hover {  }
> Traversing the DOM, or even setting up event delegation at the top  
> level is cumbersome when a simple transitionStart would do the trick.

Sorry, I might be being dense, but why is the transition event any  
easier than a regular DOM event?

In your example above, eg. pseudocode

for (el in document.querySelectorAll("#sidebar a")) {
   el.addEventListener("mouseover"...)  // this should find  
your :hover cases

... or even do it on the top level, like you say.

I'm not against transitionStart events, I'd just like to be sure we're  
not adding something that's unnecessary unless there is a wide demand  
for it. It might just be that I haven't written enough content to come  
across a case where it's essential.

Received on Monday, 27 April 2009 08:24:22 UTC

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