XML Tutorial/XML Schema/gMonthDay
The gMonthDay datatype represents a Gregorian date that recurs yearly
<!-- schema -->
<xsd:element name="birthday" type="xsd:gMonthDay"/>
<!-- instance document -->
<birthday>--10-25</birthday>
<!-- schema -->
<xsd:element name="birthday" type="xsd:gMonthDay"/>
<!-- instance document -->
<birthday>--10-25</birthday>