<attribute name="frame" use="optional"> <simpleType> <restriction base="string"> <enumeration value="void" /> <enumeration value="above" /> <enumeration value="below" /> <enumeration value="hsides" /> <enumeration value="lhs" /> <enumeration value="rhs" /> <enumeration value="vsides" /> <enumeration value="box" /> <enumeration value="border" /> </restriction> </simpleType> </attribute>