To use Firefox, ensure you’re using the appropriate driver

Starting Firefox

b = :firefox

Firefox Options

Note: this documentation has been updated for Watir 6.19, and is focused on supporting the updates made for Selenium 4.

For non-browser specific capabilities take a look at our Capabilities Guide In addition to those, there are a number of Firefox specific settings that will change how Firefox operates during the test run.

Watir will build the options for you when you pass in a Hash that is based on Selenium’s Firefox::Options class

Commonly used settings include:

  • :args - an Array of command-line arguments to use when starting Firefox
  • :binary - a String representing the Path to the Firefox Browser executable to use
  • :profile - an encoded profile string or Firefox::Profile instance
  • :log_level - the String or Symbol representing the desired log level for geckodriver
  • :prefs - a Hash with each entry consisting of the key of the preference and its value

Firefox Profiles

You can specify an existing profile to use, such as your ‘default’ profile:

b = :firefox, options: {profile: 'default'}

You can also create a new Firefox profile each test run using any of the options that you can configure in the about:config pane of Firefox

For example:

profile =
profile[''] = '/tmp/webdriver-downloads'
profile[''] = 2
profile['browser.helperApps.neverAsk.saveToDisk'] = 'application/pdf'

b = :firefox, options: {profile: profile}

Last Updated: March 12, 2021