(PHP 5 >= 5.0.1, PHP 7) Identifies an element's attributes

(PHP 5 >= 5.1.3, PHP 7) Adds an attribute to the SimpleXML element

(PHP 5 >= 5.1.2, PHP 7) Returns namespaces used in document

(PHP 5 >= 5.1.2, PHP 7) Returns namespaces declared in document