def assert_hidden(tag, element_id)
			if RWebSpec.framework =~ /selenium/i
      	perform_assertion { assert(!eval("#{tag}(:id, '#{element_id.to_s}').displayed?"), "Element '#{tag}' with id: '#{element_id}' is visible") }
			else
      	perform_assertion { assert(!eval("#{tag}(:id, '#{element_id.to_s}').visible?"), "Element '#{tag}' with id: '#{element_id}' is visible") }
			end
    end
def assert_hidden(tag, element_id)
			if RWebSpec.framework =~ /selenium/i
      	perform_assertion { assert(!eval("#{tag}(:id, '#{element_id.to_s}').displayed?"), "Element '#{tag}' with id: '#{element_id}' is visible") }
			else
      	perform_assertion { assert(!eval("#{tag}(:id, '#{element_id.to_s}').visible?"), "Element '#{tag}' with id: '#{element_id}' is visible") }
			end
    end
Assert tag with element id is hidden?, example
   assert_hidden(:div, "secret")
   assert_hidden(:span, "secret_span")