# File lib/selenium/webdriver/remote/capabilities.rb, line 148
        def as_json(opts = nil)
          hash = {
            "browserName"         => browser_name,
            "version"             => version,
            "platform"            => platform.to_s.upcase,
            "javascriptEnabled"   => javascript_enabled?,
            "cssSelectorsEnabled" => css_selectors_enabled?,
            "takesScreenshot"     => takes_screenshot?,
            "nativeEvents"        => native_events?,
            "rotatable"           => rotatable?,
          }

          hash["proxy"]           = proxy.as_json if proxy
          hash['firefox_profile'] = firefox_profile.as_json['zip'] if firefox_profile

          hash
        end