# File lib/selenium/web_page.rb, line 89
    def element_locator(how, what=nil)
      locator = how
      if (not what.nil?)
        if (how == :xpath or how == :name or how == :id)
          locator = "#{how}=#{what}"
        else
          raise "couldn't understand how to build locator using #{how} with #{what}"
        end
      end
      locator
    end