def hidden_field(name, identifier={:index => 0}, &block)
      standard_methods(name, identifier, 'hidden_field_for', &block)
      define_method(name) do
        return platform.hidden_field_value_for identifier.clone unless block_given?
        self.send("#{name}_element").value
      end
    end
def hidden_field(name, identifier={:index => 0}, &block)
      standard_methods(name, identifier, 'hidden_field_for', &block)
      define_method(name) do
        return platform.hidden_field_value_for identifier.clone unless block_given?
        self.send("#{name}_element").value
      end
    end
adds three methods to the page object - one to get the text from a hidden field,
 another to retrieve the hidden field element, and another to check the hidden
 field's existence.

 @example
   hidden_field(:user_id, :id => "user_identity")
   # will generate 'user_id', 'user_id_element' and 'user_id?' methods

 @param [String] the name used for the generated methods
 @param [Hash] identifier how we find a hidden field.
 @param optional block to be invoked when element method is called