Frozen Date objects?

Jonas Sicking jonas at
Wed Jul 17 16:55:06 PDT 2013

On Wed, Jul 17, 2013 at 4:42 PM, Brandon Benvie <bbenvie at> wrote:
> On 7/17/2013 4:36 PM, Jonas Sicking wrote:
>> Is this simply a SpiderMonkey bug? Do we expect JS code to be able to
>> handle Date objects representing timezones other than the user's
>> current timezone?
> What happens if the timezone changes between the creation of two Date
> objects, such as for daylight savings or the user changes their system
> timezone?

I believe SpiderMonkey in Firefox Desktop until recently would grab
the snapshot of the user's timezone on browser startup, and then never
change it until the browser was shut down.

Now it seems to update that snapshot now and then in some pattern that
isn't obvious to me. When that happens the timezone offset for *all*
Date instances all change.

/ Jonas

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