[Cosmo-dev] DST treatment in JS

[Matthew Eernisse]

Just a quick note -- I ran into this fun little tidbit of data yesterday 
while tracking down that Safari bug.

ECMA states that historical information should be ignored when 
calculating DST.

See 15.9.1.9, Daylight Saving Time Adjustment here:

http://bclary.com/2004/11/07/ecma-262#a-15.9.1

Apparently JS is allowed to interpolate DST from an 'equivalent year' -- 
a year with same leap-ness and same starting week day as the year of the 
date in question.

Not sure what the impact is there with the changes to DST this year here 
in the US, but it does make me very happy we have a real solution for 
timezones that pulls real DST data from the same place that everyone 
else does.


Matthew