XML Tutorial/XML Schema/anyAttribute

Attribute Wildcards

To declare an attribute wildcard, use the <anyAttribute>declaration: 
<anyAttribute namespace="allowable namespaces" 
              processContents="lax or skip or strict"> 
The <anyAttribute>declaration can appear only within a <complexType> or <attributeGroup> declaration. 
You are not allowed to create global <anyAttribute> declarations. 
The namespace attribute allows several values: 

##any allows attributes from all namespaces to be included as part of the wildcard 
##other allows attributes from namespaces other than the targetNamespace to be included as part of the wildcard 
##targetNamespace allows attributes from only the targetNamespace to be included as part of the wildcard 
##local allows attributes that are not qualified by a namespace to be included as part of the wildcard 
Whitespace-separated list of allowable namespace URIs allows attributes from any listed namespaces to be included 
  as part of the wildcard. Possible list values also include ##targetNamespaceand ##local.