nonumber
Mozilla/5.0 (Windows NT 6.1; WOW64; rv:15.0) Gecko/20120427 Firefox/15.0a1
Mozilla/5.0 (Windows NT 6.1; WOW64; rv:22.0) Gecko/20100101 Firefox/22.0
Mozilla/5.0 (Windows NT 6.1; rv:23.0) Gecko/20131011 Firefox/23.0