Chrome

ChromeDriver

Chrome support is through the platform specific ChromeDriver binary, which you download and put on your path.

b = Watir::Browser.new :chrome

Chrome Preferences

prefs = {
  download: {
    prompt_for_download: false,
    default_directory: '/path/to/dir'
  }
}

b = Watir::Browser.new :chrome, prefs: prefs

Chrome Switches

b = Watir::Browser.new :chrome,
                       switches: %w(--ignore-certificate-errors --disable-popup-blocking --disable-translate)

See the full list of switches here

Using a proxy with Chrome

b = Watir::Browser.new :chrome, switches: %w(--proxy-server=myproxy.com:8080)