id A unique ID for the element. A unique ID for the element. name Name of the attribute. Cannot be present if ref is used. Name of the attribute. Cannot be present if ref is used. ref Reference to a named attribute. Cannot be present if name is used. Reference to a named attribute. Cannot be present if name is used. type Built-in data type or a simple type. If a simpleType element is present, then type cannot be used. Built-in data type or a simple type. If a simpleType element is present, then type cannot be used. default Default value for the attribute. Cannot be present if fixed is used. Default value for the attribute. Cannot be present if fixed is used. fixed Fixed value for the attribute. Cannot be present if default is used. Fixed value for the attribute. Cannot be present if default is used. form qualified unqualified Form for the attribute. Default value is specified by the attributeFormDefault attribute in the schema element. Form for the attribute. Default value is specified by the attributeFormDefault attribute in the schema element. use optional required prohibited Specifies usage of the attribute. Specifies usage of the attribute.