这份文档http://www.w3.org/TR/NOTE-datetime详细介绍了日期和时间格式：
Examples
1994-11-05T08:15:30-05:00 corresponds to November 5, 1994, 8:15:30 am, US Eastern Standard Time.
1994-11-05T13:15:30Z corresponds to the same instant.
完整日期加上小时、分钟、秒及小数秒
YYYY-MM-DDThh:mm:ss.sTZD (例如 1997-07-16T19:20:30.45+01:00)
其中：
YYYY = four-digit year
MM = two-digit month (01=January, etc.)
DD = two-digit day of month (01 through 31)
hh = two digits of hour (00 through 23) (am/pm NOT allowed)
mm = two digits of minute (00 through 59)
ss = two digits of second (00 through 59)
s = one or more digits representing a decimal fraction of a second
TZD = time zone designator (Z or +hh:mm or -hh:mm)
1994-11-05T08:15:30中的T代表时间。