Well all I can say is I guess the W3C is right to support fewer

formats than ISO 8601. Not only does their dateTime datatype only

support "calendar date", it only allows fractions on seconds (and

doesn't allow "basic format") ...

From

http://www.w3.org/TR/xmlschema-2/#dateTime :

"

3.2.7.1 Lexical representation

The ·lexical space· of dateTime consists of finite-length sequences

of characters of the form: '-'? yyyy '-' mm '-' dd 'T' hh ':' mm ':'

ss ('.' s+)? (zzzzzz)?, where

'-'? yyyy is a four-or-more digit optionally negative-signed numeral

that represents the year; if more than four digits, leading zeros are

prohibited, and '0000' is prohibited (see the Note above (§3.2.7);

also note that a plus sign is not permitted);

the remaining '-'s are separators between parts of the date portion;

the first mm is a two-digit numeral that represents the month;

dd is a two-digit numeral that represents the day;

'T' is a separator indicating that time-of-day follows;

hh is a two-digit numeral that represents the hour; '24' is permitted

if the minutes and seconds represented are zero, and the dateTime

value so represented is the first instant of the following day (the

hour property of a dateTime object in the ·value space· cannot have a

value greater than 23);

':' is a separator between parts of the time-of-day portion;

the second mm is a two-digit numeral that represents the minute;

ss is a two-integer-digit numeral that represents the whole seconds;

'.' s+ (if present) represents the fractional seconds;

zzzzzz (if present) represents the timezone (as described below).

"

As the ISO is so much more permissive than the W3C, they probably

_should_ define formats for fractional dates. After all, they never

say what any particular value _means_ anyway.