Re: HTML Time Zone proposal

I have one comment to the proposed specification.
When a wall time is specified with a zone, the time might be invalid, or 
ambiguous during daylight saving transition (or zone offset change). For 
example,

1) <time dateTime="2014-03-09T02:30:00" tz="America/New_York"/>

The wall time 2:30 does not exist, because wall time jump to 3:00am 
(UTC-4) one second after 1:59am (UTC-5)

2) <time dateTime="2014-11-02T01:00:00" tz="America/New_York"/>

The wall time 1:00 happens twice - 1:00am (UTC-4) and 1:00am (UTC-5), so 
the actual time is ambiguous.


I think the spec should clarify how user agent should handle these cases 
(invalid / ambiguous), or just say "the behavior is undefined".


- Yoshito Umaoka