class REXML::Attributes

def prefixes


d.root.attributes.prefixes # => ["x", "y"]
d = REXML::Document.new(xml_string)
xml_string = ''

namespace declaration, if one exists.
The array does not include the default
Returns an array of prefix strings in the attributes.

prefixes -> array_of_prefix_strings
:call-seq: 
def prefixes
  ns = []
  each_attribute do |attribute|
    ns << attribute.name if attribute.prefix == 'xmlns'
  end
  if @element.document and @element.document.doctype
    expn = @element.expanded_name
    expn = @element.document.doctype.name if expn.size == 0
    @element.document.doctype.attributes_of(expn).each {
      |attribute|
      ns << attribute.name if attribute.prefix == 'xmlns'
    }
  end
  ns
end