[webkit-dev] Differentiating between JS object properties and DOM attributes

[Darin Adler]

On Mar 9, 2007, at 4:32 PM, Christian Cantrell wrote:

> I recently noticed something that surprised me in a new build of  
> WebKit.  I found that some dashboard widgets don't run, including  
> some Apple widgets like Stocks.  When I investigated, I found that  
> some widgets access custom DOM attributes using dot notation rather  
> than the getAttribute function.  For instance, with HTML like this...
>
> <table>
> 	<tr id="tr" foo="bar">
> 		<td>hi.</td>
> 	</tr>
> </table>
>
> ... they might access the value of foo like this...
>
> document.getElementById("tr").foo;
>
> ... rather than this...
>
> var tr = document.getElementById("tr").getAttribute('foo');
>
> I understand that this is considered a "fix" or a move toward more  
> standardization, but I'm worried that this will break a lot of  
> existing content, including some dashboard widgets written by Apple.

That's right. It was this change, made about a year ago: <http:// 
trac.webkit.org/projects/webkit/changeset/14069>.

It's not a "fix" in quotes -- it's a real life fix to actual  
websites. It was motivated by the desire to fix those sites, not an  
abstract urge for standardization.

Ultimately when we need a change like this for website compatibility  
we have a tough decision to make about WebKit-specific content like  
widgets that has not been tested with other engines. In some cases we  
create application-specific quirks, but we try to avoid creating long  
term differences between, say, the behavior of Dashboard and Safari  
with the same content.

> Does anyone have an insight into this issue? Will everyone just  
> need to update their content when Leopard comes out?

Yes, some widgets will need to be updated. There's no need to wait  
for Leopard to come out; an updated widget would be backward compatible.

As far as websites are concerned, I assume few sites depend on this  
behavior since Firefox's Gecko matches the new WebKit behavior.

     -- Darin