def assert_visible(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}' not visible") }
			else
			  perform_assertion { assert(eval("#{tag}(:id, '#{element_id.to_s}').visible?"), "Element '#{tag}' with id: '#{element_id}' not visible") }
			end
    end
def assert_visible(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}' not visible") }
			else
			  perform_assertion { assert(eval("#{tag}(:id, '#{element_id.to_s}').visible?"), "Element '#{tag}' with id: '#{element_id}' not visible") }
			end
    end
Assert tag with element id is visible?, eg.
   assert_visible(:div, "public_notice")
   assert_visible(:span, "public_span")