XML Schema - mixed element content

The text content (textual child nodes) can not be validated.

The child elements can be validated.

Example:

<xs:element name="book"> 
 <xs:complexType mixed="true">
  <xs:all>
   <xs:element name="title" type="xs:string"/>
   <xs:element name="author" type="xs:string"/>
  </xs:all> 
  <xs:attribute name="isbn" type="xs:string"/>
 </xs:complexType> 
</xs:element>