# Executing JavaScript

Executing JavaScript requires automating a browser.

=== "Ferrum"

    ```ruby
    class DummyJob < Wayfarer::Base
      route { to :index }

      def index
        browser.evaluate("[window.scrollX, window.scrollY]")
      end
    end
    ```

=== "Selenium"

    ```ruby
    class DummyJob < Wayfarer::Base
      route { to :index }

      def index
        # Mind the explicit return
        browser.execute_script("return [window.scrollX, window.scrollY]")
      end
    end
    ```

=== "Capybara"

    ```ruby
    class DummyJob < Wayfarer::Base
      route { to :index }

      def index
        # Capybara does not return value of JavaScript execution
        browser.execute_script("console.log('Foobar')") # => nil
      end
    end
    ```