2.1.7 [W3C-XSD] Section 184.108.40.206, 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).
MSXML6, IE9 Mode, IE10 Mode, and IE11 Mode (All Versions)
Leading zeros are accepted if yyyy is more than four digits, such as 01987-10-12T00:00:00.