---excerpt from: [http://www.ecma-international.org/ecma-262/5.1/#sec-126.96.36.199]
"The value of an absent time zone offset is “Z”."
>> Date.parse('2011-11-29T15:52:18.867') === Date.parse('2011-11-29T15:52:18.867Z')
this is incorrect and contrary to what the ECMA spec states for date parsing of ISO8601 strings. Other browsers have been doing this correctly for a while now (Opera and Chrome both are standards compliant in this regard), it'd be nice if IE didn't need a shim to bring it up to standards compliant behavior.
this also runs contrary to your own documentation:
"Z The value in this position can be one of the following. If the value is omitted, UTC time is used.
Z indicates UTC time.
+hh:mm indicates that the input time is the specified offset after UTC time.
-hh:mm indicates that the input time is the absolute value of the specified offset before UTC time."
-- why was this closed as non-reproducible?