[whatwg] DOMTimeStamp binding
Kartikaya Gupta
lists.webapps at stakface.com
Thu Feb 12 07:08:59 PST 2009
On Wed, 11 Feb 2009 15:03:01 -0800, Darin Adler <darin at apple.com> wrote:
>
> On Feb 11, 2009, at 12:14 PM, Kartikaya Gupta wrote:
>
> > I updated to Safari 3.2 on Windows (which looks it also has WebKit
> > 525.27.1) and you're right, it is now showing "number" instead of
> > "object". I guess this was changed not too long ago. So then my
> > question is: why was it changed?
>
> No, this was not changed.
>
> I don't understand why you were getting that strange result, but
> WebKit has always shown "number" for this. I went back to old
> versions, including digging out a copy of Safari 2 and every version I
> tested yields a number. There was never any code that attempted to
> return anything except a number.
Well, I don't know what to tell you. Latest version of Chrome is still giving me a Date object. I don't know what version of WebKit it's using.
> More to the point, there's also a false premise in the specification's
> claim that this should be a Date. The Date class in JavaScript boils
> down to a double for its internal representation; I believe that's by
> design and not just a detail of the WebKit implementation. So the
> claim that a number, also a double, can't handle the entire range of
> DOMTimestamp, but the Date class can is probably incorrect. Maybe
> someone can give a specific example with details of how this would go
> wrong I dont think there is any such example.
>
The DOM 3 Core actually says that an "integer type" in ECMAScript is too small. The ECMA-262 spec doesn't say anything about an "integer" type; all numbers are doubles, so I have no idea what the DOM spec is referring to. However, note that section 15.9.1.1 of ECMA-262 does says that the valid range for a Date object is slightly smaller than that representable by a double (8,640,000,000,000,000 milliseconds on either side of epoch, instead of 9,007,199,254,740,991), so there is a slight difference between returning a number and returning a Date. However, in practice it's unlikely those scenarios will be hit.
Cheers,
kats
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