The 'simpleContent' element can be used to extend a simple type to add attributes.

The 'extension' element child contains some number of attribute declarations.

The content of the element remains typed as the simple type referenced via the 'base' attribute on 'extension'.

Example:

<xs:complexType name="Anchor">
   <xs:simpleContent>
     <xs:extension base="xs:string">
       <xs:attribute name="href" type="xs:anyURI"/>
     </xs:extension>
   </xs:simpleContent>
</xs:complexType>

There is a child call 'restriction' that can be used in place of 'extension'. That will be discussed in the lecture on simple types.