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Re: [cssom-view] unrestricted double in ScrollToOptions

From: Simon Pieters <simonp@opera.com>
Date: Mon, 02 Mar 2015 14:10:35 +0100
To: www-style@w3.org
Cc: "Kip Gilbert" <kgilbert@mozilla.com>, ajuma@chromium.org
Message-ID: <op.xuvf7xr1idj3kv@simons-mbp>
On Fri, 27 Feb 2015 10:25:17 +0100, Simon Pieters <simonp@opera.com> wrote:

> The CSSOM View spec uses `double` in ScrollToOptions top/left dictionary  
> members, which means that non-finite numbers throw TypeError per WebIDL.
>
> http://dev.w3.org/csswg/cssom-view/#dictdef-scrolltooptions
>
> The spec uses `unrestricted double` (and converts non-finite numbers to  
> zero) for the arguments that were traditionally `long`, since it matches  
> the traditional `long` behavior.
>
> Example: scrollTo(0, NaN); // same as x.scrollTo(0, 0);
>
> The ScrollToOptions dictionary is new so there is no Web compat to worry  
> about.
>
> Example: scrollTo({top: NaN}); // throws TypeError per spec
>
> However, in Gecko and Blink they are implemented as `unrestricted  
> double`; non-finite numbers do not throw TypeError. (Blink doesn't  
> convert Infinity to zero, this is a known bug.) Should we change the  
> spec to make ScrollToOptions top/left `unrestricted double`, so that the  
> dictionary behaves more like the old arguments? Or do people think it is  
> more useful to throw for non-finite numbers in the dictionary?

kip, ajuma, any opinions?

cheers
-- 
Simon Pieters
Opera Software
Received on Monday, 2 March 2015 13:10:44 UTC

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