class UserAgent::Browsers::Webkit

def version

Prior to Safari 3, the user agent did not include a version number 
def version
  str = if product = detect_product('Version')
    product.version
  elsif os =~ /iOS ([\d\.]+)/ && browser == "Safari"
    $1.tr('_', '.')
  else
    BuildVersions[build.to_s]
  end
  Version.new(str)
end